The British embassy in Yemen will be closed on Sunday and MondayThe British embassy in Yemen is to shut temporarily and several other embassies have been told to be vigilant after the US issued a global travel alert.
The embassy in Sana'a will be closed on Sunday and Monday as "a precautionary measure", the Foreign Office said.
A spokesman would not say if the closure was due to a specific threat.
According to the New York Times, the US - which is to close 21 of its embassies on Sunday - has intercepted al-Qaeda messages discussing possible attacks.
The British embassy in Yemen had already been operating with a reduced staff "due to increased security concerns".
A number of British embassies in the Middle East have been warned about the latest threat.
'Emanating from Yemen'Robin Simcox, a research fellow at the Henry Jackson Society, which monitors threats from al-Qaeda, said US authorities had intercepted communications "between senior al-Qaeda leaders talking about an operational and clearly viable plot against an embassy".
He said it is unclear which embassy that is, but Yemen is a high-risk country because the US has stepped up drone attacks there in recent days and al-Qaeda's "most active franchise" is based in the Arabian Peninsula.
There had been a "lull" in US drone attacks in Yemen in the last two months, and Mr Simcox said the sudden increase suggests the latest threat is "emanating from Yemen itself".
A Foreign Office spokesman said: "The embassy will be closed on 4 and 5 August. We have withdrawn a number of staff from Sana'a, due to increased security concerns.
"We updated our travel advice to Yemen on 2 August to reflect that.
"We keep travel advice and the security of our staff and missions under constant review. Our travel advice advises particular vigilance during Ramadan, when tensions could be heightened.
"We are particularly concerned about the security situation in the final days of Ramadan and into Eid."
The Islamic holy month ends next week.
'Leave now'Iona Craig, the Times' correspondent in Yemen, said very few British people now remain in the country, and that "the threat to foreigners here has definitely increased" in recent months.
She told BBC Radio 4's Today programme British embassy staff in Yemen now live on-site, following two attacks in 2010.
- In April 2010, a suspected al-Qaeda suicide bomber tried to kill the British ambassador to Yemen in Sana'a. No one except the attacker was killed.
- In October 2010, militants fired a rocket-propelled grenade at a car carrying Britain's deputy ambassador in the Yemeni capital. One embassy worker and two bystanders were injured.
On its website, the Foreign Office was already advising against all travel to Yemen and urging British nationals to "leave now".
It says there is "a high threat from terrorism throughout Yemen" and "a very high threat of kidnap from armed tribes, criminals and terrorists".
Unlike the US, the UK is keeping its embassies in Saudi Arabia, Oman, Qatar, Bahrain, Kuwait, United Arab Emirates and Iraq open, but it has advised staff to "exercise extra vigilance as we approach Eid".
The US state department responded to the threat by issuing a global travel alert.
In a statement, 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."
