Government sources admitted yesterday that 28,000 ground troops backed by special forces, aircraft and artillery have moved into the attack in an operation which bears all the marks of a military “surge” aimed at defeating an estimated 10,000 insurgents in this troublesome region.

This is almost four times larger than the British force currently fighting in Helmand Province.

According to local reports, two Pakistani infantry divisions are involved in the current fighting. Troops are thought to be closing in on three fronts – towards the northern town of Razmak, between North and South Waziristan; from Jandola in the east; and from Shakai in the west.

Other targets include Makeen, Spinkai Raghzai and Tiarza.

The operations were ordered as a result of a string of brazen attacks which caused 170 casualties and humiliated the security forces by targeting key government buildings.

Before yesterday’s assault began, Interior Minister Rehman Malik warned that unless the terrorists were stopped in their heartlands, Pakistan would face meltdown.

“The enemy has started a guerrilla war,” he said on Friday. “These attacks are a moment of reflection for us – but you will soon see these Taliban, these hired guns, fleeing. The whole nation should be united against these handful of terrorists, and, God willing, we will defeat them.”

Thought to be the responsibility of the Tehrik-e-Taliban terrorist group, the recent attacks in Lahore, Rawalpindi and Peshawar were carefully planned and followed a pattern familiar to the security forces in Afghanistan. Following the detonation of bombs, usually in quick succession, Taliban gunmen moved into the area, killing indiscriminately and causing panic and chaos in the streets.

Thursday was a typical example of what happened last week and shows why these urban attacks are so difficult to counter. In Lahore, the violence began after 9am when gunmen attacked the local headquarters of the Federal Investigation Agency, killing four employees and an innocent bystander.

Almost immediately afterwards, a second group of gunmen attacked a police training school in the suburb of Manawan, killing nine officers. This was followed by a third attack on a police commando training centre where a constable and a civilian were killed. A police spokesman claimed later that three of the 13 terrorists involved in the attack were women.

There are also suspicions that Tehrik-e-Taliban has been receiving information from sources within the Pakistani Army or the Inter-Services Intelligence agency (ISI). Not only were the attacks well co-ordinated but the fighters also had accurate intelligence about the targets and their defences.

The Talibanisation of the ISI has long been suspected – the secretive intelligence organisation has been responsible for funding terrorist groups such as Lashkar-e-Taiba whose doctrine embraces worldwide jihad – but this is the first time that there have been concerted and concentrated Taliban attacks on main civic centres.

Other groups involved in the attacks are thought to include al-Qaeda and the Islamist groups Lashkar-e-Jhangvi and Jaish-e-Mohammad. As a Pakistani general put it, “we are now on a war footing against a determined enemy”.

At the same time, while Pakistani security forces were dealing with the terrorist attacks on home ground, strike aircraft were taking the battle to the Taliban in the tribal territories which act as a buffer between Pakistan and Afghanistan. In moves which would have been impossible a year ago, Pakistani war planes carried out raids against suspected terrorist targets in South Waziristan while ground forces carried out mopping-up operations.

“These attacks have links with militants in South Waziristan,” claimed Rana Sanaullah, Punjab province’s law minister. “Investigations are focusing on when these people came to Lahore, where they stayed and who their contacts were in the city.”

The tactical situation is familiar to Nato commanders in Afghanistan, where one of the main issues is the porous nature of the frontier between the two countries and the ability of terrorist groups to find safe havens in the tribal territories. All too often Taliban and al-Qaeda groups mount attacks in Afghanistan and then melt away over the border, preventing any hot pursuit. Their tactics have encouraged the US to use unmanned drones to carry out precision attacks on villages or compounds suspected of housing terrorists, but their deployment has angered Pakistani politicians, especially when civilians are killed in the attacks.

That is why the operations in South Waziristan are so unexpected. Although Pakistan signed up to the US war against terrorism under General Pervez Musharraf, there was often an unwillingness among senior commanders to mount offensive operations in the tribal territories. Not only were they considered to be more trouble than they were worth, but it was also thought that they would further destabilise the country and cause unacceptably high casualties in return for few strategic gains.

With this weekend’s surge, Pakistani army commanders have changed their tune. The main reason is that President Asif Ali Zardari has signed up to US President Barack Obama’s “Af-Pak” policy, which insists that the core of the strategy in Afghanistan lies in embracing security issues on both sides of the border. US State Department officials have long argued that Pakistan is the key to regional security – and that it has to be encouraged, rather than bludgeoned as it was during the previous presidency.

One US diplomatic source said that “Bush treated Musharraf like a naughty child” whereas Obama wants Zardari to be a grown-up partner who has a stake in future US policy. In return for mounting satisfactory operations against terrorist targets in the tribal areas, Pakistan has been offered additional US financial aid of $7.5 billion. This is an important consideration is a country with a fragile economy and constant political instability. The US also wants firm guarantees that Pakistan’s nuclear arsenal is in safe hands. For Pakistan this is both a challenge and an opportunity: Dr Nasrullah Mirza, a visiting fellow at the Royal United Services Institute, a Whitehall think tank, believes that the solution is central to the country’s future well-being.

“With the implementation of the Af-Pak strategy the dilemma for Pakistan’s army is two-fold,” he argues. “First, it must co-operate with the US to eliminate al-Qaeda elements and counter militant Taliban in its tribal areas and beyond, or compromise its sovereignty by allowing the US to do the job. The promises of aid from the US have been more intricately tied to such co-operation than ever before.

“Second, if the army fails to get tough on the Taliban, which it nurtured in the 1980s during the war in Afghanistan, Pakistan risks international isolation.”

Some indication of the Pakistani Army’s willingness to address those concerns will be seen in the outcome of the current preparations in South Waziristan, an area ruled by an alliance of Taliban commanders, Uzbek and al-Qaeda militants. The aim is to break their power structure by hitting known and suspected leadership centres. Already thousands of civilians have left the area and all major exit routes have been closed, while the targets have been hit by Pakistani strike aircraft.

Senior commanders say that the level and intensity of the planning gives the lie to claims that they have not signed up to Obama’s Af-Pak strategy and claim that there is more to come before winter puts a stop to sustainable campaigning in the high mountains.

In contrast to the recent summer operations in the Swat valley, which allowed terrorists to escape, the Pakistani Army is now intent on killing the opposition through air strikes and ground offensives. These “decapitation” operations are intended to weaken the Taliban and prevent them dispersing into other tribal areas or over the border into Afghanistan.

At the same time, the Pakistani Army will mount fresh operations to secure the main transport arteries as well as the high ground, especially in centres dominated by the Mehsud, including Ladha, Makeen and Sararogha, which hitherto have been regarded as no-go areas. The Mehsud make up two-thirds of South Waziristan’s population and have been a thorn in the flesh for successive administrations – including the British during the 19th century.

Success in South Waziristan will not just help to put a stop to the kind of terrorist outrages which visited the streets of Pakistan last week. It will also help to give a clue to Obama as he ponders the next stage in his Afghanistan policy.

Already divisions have opened up between his main advisers. General Stanley McChrystal, the main Nato commander, has called for a counterinsurgency strategy that focuses on winning over Afghans, not just killing insurgents. With the backing of defence secretary Robert Gates he has asked for 40,000 additional troops to do the job.

On the other hand, a growing number of White House foreign policy advisers led by the vice-president, Joe Biden, have advocated a slimmed-down operation aimed at rooting out al-Qaeda. At the same time there would be a heavier reliance on Pakistani forces.

This option would require little change in US troop levels – an important consideration at time when opinion polls show falling support for operations in the war against terrorism and increasing scepticism about the legitimacy of the current Afghan administration. Biden and his cohorts will be watching with more than usual interest the outcome of the current operations in South Waziristan.