BBC Arabic quoted a Yemeni security source as saying that "extraordinary and unprecedented" security measures had been put in place, with armored vehicles deployed at the presidential palace and other sensitive government and foreign installations in Yemen's capital.
Dozens of al-Qaeda operatives were said to have streamed into Sana'a in the last few days, apparently to take part in a terrorist attack. The Yemeni claim could not be independently confirmed.
Hours earlier, Yemeni tribal sources and unnamed officials reported two US drone strikes that killed four suspected al-Qaeda operatives in Marib province north-east of Sana'a, including a senior commander who was named by al-Jazeera as Salah al-Jumati.
The New York Times reported that US intelligence services had intercepted communications between Ayman al-Zawahiri, al-Qaeda's overall leader, and the Yemeni head of al-Qaeda in the Arabian Peninsula (AQAP), Nasser al-Wuhayshi.
The paper quoted counter-terrorism officials as saying that Zawahri had recently elevated Wuhayshi to be the new "general manager" of the terrorist network, making him the second most important man in the organization.
The US State Department called on American citizens in Yemen to leave the country “immediately” because of security concerns.
In a similar move, Britain's Foreign Office said that it had evacuated all staff from its embassy in Yemen due to security concerns, adding that the British embassy staff were "temporarily withdrawn to the UK" on Tuesday.
DEBKAfile reported on Monday that the United States ordered its warships in the Middle East to be ready in case of a possible terror attack by al-Qaeda.
US Secretary of Defense Chuck Hagel “is considering a special deployment of US forces in the Middle East ready for action if a terrorist attack makes it necessary,” according to the report.
“US warships have been ordered to sail into waters opposite Yemen, which is reported to be the source of the terrorist threat which has closed 19 US embassies and consulates in the Muslim world since Sunday,” DEBKAfile reported.
Some analysts believe that a terrorist threat at this time can help Washington divert attention from the uproar over the NSA’s spying programs.
SHI/SHI