TWO car bombs explode in a Damascus street killing 55 innocent bystanders and injuring many more, a lone terrorist is foiled before he can explode a sophisticated new underwear bomb on a US-bound airliner, in Mali a British hostage is offered his freedom in return for the release of the London-based radical cleric Abu Qatada while in Pakistan – al-Qaeda leader Ayman al-Zawahiri calls on Muslims to avenge the recent burning of Qurans by US soldiers in Afghanistan.

This is the new and worrying world of al-Qaeda, which has spent the last year busily extending its franchises in the Middle East, Arabia and North Africa. In May last year the US thought that it had decapitated the terrorist organisation by killing its founder Osama bin Laden in his hiding place in Abbottabad in Pakistan. But a year later al-Qaeda is still flourishing, albeit in a very different form from its shadowy origins in Afghanistan where bin Laden and his associates plotted the airliner attacks on the US homeland in September 2001.

It sounds worrying and it is – al-Qaeda is still highly dangerous – but the good news is that the west together with a number of crucial Arab allies have made progress in countering the threat. The fact that the underwear bomber did not get through to attack the US was due to the efforts of one man – an unnamed Saudi Arabian double agent with a British passport who risked his life by targeting the notorious bomb maker Ibrahim Hassan al-Asiri who is also one of the leading commanders in al-Qaeda in the Arabian Peninsula (AQAP)

From the very beginning of the war against terrorism US intelligence agencies have had problems getting inside the mindset of al-Qaeda and that absence of real-time human intelligence held back operations. The one blot has been the leaking of information about the double agent. The FBI is conducting a separate criminal investigation and the US defence secretary, Leon Panetta, a former CIA director, made his anger clear on Friday when he said: "When these leaks take place, they damage our ability to be able to pursue our intelligence efforts."

However, if the use of double agents shows how far the US has come in its struggle against Islamic terrorism the killing of eight al-Qaeda commanders in Yemen demonstrates its capacity to strike at will against terrorist targets. Last week missiles from an unmanned drone hit a target in the town of Jaar, an al-Qaeda stronghold in Abyan province, killing all the occupants in a safe house used by AQAP. Although the result of the strike was gratifying to US officials who rarely provide accurate details about such operations it does confirm that far from being a spent force al-Qaeda is slowly extending its influence across the Islamic world from Iraq, through the Arabian peninsula to the Maghreb, the north African coast.

IRAQ (AQI)

Last week's car bombings in Syria marked a worrying trend in the long-running internecine war in Syria. The world has grown used to the sight of Syrian tanks and artillery bombarding cities such as Homs and Hama but here were graphic images of civilians cut down by the equally familiar car bomb, a device which has only been used recently in the country. Early on Thursday morning in Damascus the weapons exploded near a busy junction while children were on their way to school and people were on their way to work.

According to government officials the bombs were similar to those deployed by al-Qaeda groups in neighbouring Iraq and that has led to fears that AQI has now involved itself in the war between the Syrian armed forces and groups opposed to them including the Free Syrian Army. While President Bashar al-Assad is keen to play up the possibility that AQI is behind the present trouble in Syria – he makes constant reference to "foreign terrorists" – there is US evidence that AQI has hi-jacked the uprising to extend its influence in the country.

There are other connections. AQI is largely a Sunni-based organisation, which has been using its resources to attack Shia targets in Iraq and it would be a logical extension of those efforts to strike at the Syrian Alawite government which depends on Shia support for its existence. "This is opportunism, pure and simple," a US intelligence source told the Sunday Herald. "It's highly probable that the attacks in Syria were ordered by Ayman al Zawahiri who took over al-Qaeda's Pakistan-based central command following bin Laden's removal."

Although al-Qaeda never had a presence in Iraq prior to the US-led invasion in 2003 it prospered during the civil war which followed and used the power vacuum to establish itself within the country. Suicide bombs became a favoured weapon and their use in Syria could signal a fresh attempt by AQI to establish a new base in order to launch attacks in neighbouring countries and against western targets in the region.

ISLAMIC MAGHREB (AQIM)

Based originally in Algeria AQIM is also known as the Salafist Group for Preaching and Conduct and has extended its activities to include attacks on western targets. It also enjoys links with Al-Shabab in Somalia and Boko Haram in Nigeria, both of which share similar aims and have built up extensive links within the al-Qaeda network. US intelligence also suggests that AQIM has extended its influence into northern Mali, an area the size of France which includes the cities of Gao, Kidal and Timbuktu.

While countries such as Algeria, Tunisia and Morocco have spent years fighting radical Islamic groups AQIM's push south towards the Sahara has ignited fears that they could regroup there and challenge long-established regimes in the Maghreb. For example, in March Tuareg fighters in Mali took advantage of a coup in the capital, Bamako in order to establish a small Islamic state in the region. This led to fears that the area could become as lawless as parts of Afghanistan and Pakistan – with predictable results for the international community.

As happened in Yemen al-Qaeda groups are intent on imposing Sharia law and removing evidence of western decadence and while this has led to localised punishments including whipping of transgressors who drink alcohol or exhibit provocative images it could be the thin edge of the wedge. With stable governments to the north the southern Saharan region is virgin territory for AQIM and western diplomats are now concerned that al-Qaeda will tighten its grip there by turning it into a no-go area and increasing activities such as the kidnapping of western visitors.

According to a Malian defence official this process has already started "with about 100 north Africans, essentially from Algeria, Tunisia and Libya, who have joined the ranks of al-Qaeda in the Islamic Maghreb."

In an attempt to reassure Arab peoples that the US is not completely anti-Islam a State Department official claimed last month that "we're only at war with al-Qaeda".

The trouble is that the virus is not just resident in Afghanistan and Pakistan but has spread rapidly to other parts of the Islamic world where it has taken root and will be very difficult to eradicate.

THE ARABIAN PENINSULA (AQAP)

Based in Yemen, the original purpose of the franchise was to attack targets within the country and neighbouring Saudi Arabia, but now it has changed the focus of its attacks to the US.

Last week head of the FBI Robert Mueller claimed AQAP posed "the most serious threat to the United States" and called for increased vigilance to defend the homeland.

For some time Anwar al-Awlaki (pictured below), a radical American Muslim cleric of Yemeni descent, was a key figure in AQAP and his overt endorsement of violence as a religious duty is believed to have inspired new recruits to Islamist militancy worldwide. Al-Awlaki was killed on September 30, 2011, in northern Yemen's al-Jawf province by missiles fired from US unmanned aerial drones.

Formed in 2009 AQAP has straightforward if obvious aims: "the expulsion of Jews and crusaders" from the region; the re-establishment of an Islamic caliphate; the introduction of Sharia Islamic law; and the liberation of Muslim lands. With that in mind the US has resumed its military support for the beleaguered Yemeni regime following the earlier transfer of power, which saw the ousting of President Ali Abdullah Saleh, once seen as a vital partner in US counter-terrorism efforts in the region.

Last week Pentagon spokesman John Kirby said US military mentors had returned to the country and were actively involved "in working with the government of Yemen and the Yemeni military - to help them deal with the growing threat of al Qaeda in Yemen."

Although Kirby gave no details it was notable the announcement was made in the wake of the revelation of the foiling of the underwear bomb plot: the US clearly takes seriously the threat to its interests not just in Yemen but also in Saudi Arabia. The drones which are being used as part of the US operations in Yemen are still a controversial weapon but last month President Barack Obama's principal security advisor John Brennan defended their deployment. "Al-Qaeda's a cancer throughout the world, it has metastasised in so many different places," he said, "and when that metastasised tumour becomes lethal and malignant, that's when we're going to take the action we need to."