SANAA: Yemeni security forces, under US pressure to rein in extremists, Wednesday captured a key Al-Qaeda leader believed to be behind threats that saw foreign embassies in Sanaa closing their doors, police said.

Mohammed al-Hanq had evaded arrest on Monday during a security force raid in Arhab, 40 kilometres (25 miles) north of Sanaa, in which two of his relatives were killed and three other people wounded.

He was arrested Wednesday, along with two others who were wounded in the attack, at a hospital in the province of Amran, north of Sanaa, a security official said.

The US embassy, followed by the British and the French missions, had closed over security concerns prompted by fears of an Al-Qaeda threat against foreign interests just days after a failed attack on a US airliner claimed by the Al-Qaeda franchise in Yemen.

The US mission cited "successful" security operations north of the capital as it reopened for business on Tuesday, saying that Yemeni security forces had addressed a "specific area of concern" the previous day -- thought to be a reference to the crackdown on Hanq's group.

The British and French embassies resumed operations on Wednesday, although the British mission kept its consular services shut.

Yemen's interior ministry has given the assurance that all foreign missions and interests in Yemen are "safe," saying security measures around embassies and the residences of foreigners had been reinforced.

The ministry also said it arrested five "terrorist elements" during the past two days near Sanaa, but gave no details.

Long-standing concerns that Yemen, a country on the southern tip of the Arabian peninsula, has become a haven for Islamic terror groups were thrown into sharp focus when a Nigerian man allegedly trained in Yemen was charged with trying to blow up a US-bound jet.

The botched Christmas Day attack was claimed by Al-Qaeda in the Arabian Peninsula (AQAP), which also urged attacks on Western interests in Yemen.

The would-be bomber, Umar Farouk Abdulmutallab, 23, reportedly confessed to being trained by an Al-Qaeda bombmaker in Yemen for the suicide mission on the Northwest flight from Amsterdam to Detroit.

Explosives allegedly sewn into the man's underwear failed to detonate, and passengers jumped on him.

In the wake of the failed attack, General David Petraeus, the US regional military commander, jetted into Sanaa for talks with Yemeni President Ali Abdullah Saleh.

At the same time, Yemen sent army reinforcements to the eastern provinces of Abyan, Bayada and Shawba, where Al-Qaeda militants have hideouts, and raised the alert level in those regions.

Petraeus, according to the Saba news agency, reaffirmed Washington's support for Yemen in its efforts to fight terrorism.

He also delivered a message from US President Barack Obama related in particular to bilateral cooperation in the fight against terrorism and piracy.

On Monday US Secretary of State further upped the pressure on Yemen, saying the lack of security in the impoverished country has international ramifications.

"The instability in Yemen is a threat to regional stability and even global stability," Clinton told reporters in Washington.

The situation in Yemen, where aside from Al-Qaeda setting up lairs in remote mountainous regions the government is battling a Shiite rebellion in the north and facing down secessionists in the south, prompted Obama on Tuesday to suspend transfers of freed Guantanamo Bay inmates to the country.

The US administration is under intense pressure from domestic critics not to send more detainees back to Yemen, because of fears they will slip back into extremism in the Arab nation where Obama says the thwarted bombing was planned.

Obama also lambasted US intelligence on Tuesday, saying it had missed "red flags" in the Arabian peninsula that could have disrupted the plot to blow up the US-bound plane, vowing to stop future lapses.

The United States has also unleashed a barrage of measures to stop would-be attackers riding planes into the country, overhauling its terror watchlists and adding dozens more suspects to "no-fly" lists.

Further boosting security measures, all travellers coming from or via 14 "terror linked" countries, among them Yemen, will have to undergo compulsory enhanced screening.