The United States and Britain closed their embassies in Yemen yesterday over security concerns about possible militant attacks after the failed bombing of a US-bound plane on Christmas Day.

The US Embassy said it had received a threat by al Qaeda, which US intelligence agencies believe has a growing presence in the poor Arab country.

A British Foreign Office spokeswoman cited security reasons for the embassy’s closure but declined to say if any specific threat had been made.

Yemen has already tightened security on its coastline to stop Islamist militants infiltrating from Somalia and held talks with a US general on strengthening cooperation.

But Foreign Minister Abubakr al-Qirbi said his government was not coordinating strikes against al Qaeda with the United States.

A Nigerian man, charged with trying to bomb a Detroit-bound passenger plane on Christmas Day, is believed to have received training from the militant group in Yemen.

Al Qaeda said the attempt was in retaliation for US involvement in Yemen. In Washington, a senior aide to President Barack Obama said the United States has indications al Qaeda was planning an attack against a target in Sanaa.

Meanwhile, Yemen's president met a top US general on Saturday to discuss boosting military cooperation, after President Barack Obama tied al Qaeda's regional arm to the attempt to blow up a US passenger jet.

US General David Petraeus met President Ali Abdullah Saleh for talks focusing on strengthening security, military and economic cooperation. Petraeus also handed over a letter from Obama. Details of the letter were not released but on Friday Obama said Al Qaeda in the Arabian Peninsula, based in Yemen, appeared to have trained, equipped and directed the Nigerian who tried to bomb the flight.