INTERPOL has issued a worldwide security alert over a series of al-Qaeda linked prison breakouts amid fears of an imminent terrorist attack.

The international police agency advised states to increase vigilance after the prison breaks in Iraq, Libya and Pakistan in the past month.

It follows a worldwide travel alert from the United States to American citizens, warning al-Qaeda could be planning attacks in August, particularly in the Middle East and North Africa.

The US has also closed 21 embassies and consulates that would normally be open today, the first day of the working week in Muslim countries, including those in Bahrain, Israel, Jordan, Kuwait, Libya, Oman, Qatar, Saudi Arabia, Yemen, Afghanistan and Bangladesh.

The British embassy in Yemen will be kept closed today and tomorrow due to "increased security concerns".

France will also close its embassy in Yemen for several days. French President Francois Hollande said yesterday: "We have elements that lead us to believe that the threat is very serious and other countries have also taken similar steps."

Prison breaks took place in ­Pakistan on July 31 in a Taliban-led operation. Around 500 convicts, including senior al-Qaeda operatives, also escaped from Iraq's Abu Ghraib prison overnight on July 22.

More than 1100 inmates broke out of a prison on the outskirts of Benghazi in Libya on July 27.

In a statement issued from its headquarters in Lyon, France, Interpol said al-Qaeda involvement was suspected in several breakouts.

It requested help "to determine whether any of these recent events are co-ordinated or linked".

The alert noted that Wednesday marks the 15th anniversary of the US Embassy bombings in Tanzania and Kenya, which killed more than 200 and injured 4000, and brought al-Qaeda mastermind Osama bin Laden to notice for the first time.

The US is thought to have issued the worldwide travel alert after intercepting communications between senior al-Qaeda figures.

The State Department particularly warned of attacks in the Middle East and North Africa, possibly occurring in or emanating from the Arabian Peninsula.

It said: "Current information suggests that al-Qaeda and affiliated organizations continue to plan terrorist attacks both in the region and beyond, and that they may focus efforts to conduct attacks in the period between now and the end of August."

Among the most prominent of al-Qaeda's affiliates is Yemen-based group al-Qaeda in the Arabian Peninsula (AQAP), whose attacks included the Christmas Day 2009 bid to blow up a Northwest Airlines flight from Amsterdam to Detroit.

US security sources said the current threat was related to AQAP. There was no specific target and and all Western interests were at risk.

The Foreign Office in the UK was yesterday advising against all travel to Yemen and "strongly urged" Britons to leave the country, as it is "extremely unlikely" that their evacuation could be arranged if the security situation deteriorates.

UK embassies in Arab states have been advised to exercise "extra vigilance" in the run-up to the Muslim festival of Eid on Thursday.

l Nine people, including children, were killed in a suicide bomb at an Indian consulate in Afghanistan yesterday. Most of the civilian victims were inside a mosque adjacent to the consulate in Jalalabad.

The Taliban denied it was responsible for yesterday's attack, which was close to Pakistan's border.