Twenty two US diplomatic posts have been shut over the threats
Four suspected al Qaeda members have been killed in a drone strike in Yemen after a decision to shut 22 US diplomatic missions was made following a terror threat phone call.
Intelligence from telephone conversations last week between the head of al Qaeda, Ayman al Zawahiri, and the head of its affiliate in Yemen, Nasser al Wuhayshi, revealed plans to carry out an attack as early as last Sunday.
The plot is thought to have been one of the most serious against American and other Western interests since the September 11, 2001, attacks, according to US intelligence officials.
Phone conversations between al Zawahiri and al Wuhayshi were intercepted : Picture: http://news.sky.com
One official told the New York Times: "This was significant because it was the big guys talking, and talking about very specific timing for an attack or attacks."
But the exact location or target of the attacks was not revealed in the conversations.
Five missiles hit a vehicle in Marib Province in central Yemen on Tuesday killing all of its occupants, according to Yemeni tribal leaders.
The state news agency reported that four suspected al Qaeda militants were killed.
Yemeni authorities also issued a statement listing its "25 most wanted terrorists" and stated they were planning to carry out attacks in the country during the Muslim Eid al Fitr holiday this week.
It is unclear whether those killed in the strike were involved in the US plot and the US does not comment publicly on its drone attacks in Yemen.
The US has extended the closure of some of its embassies in the Middle East and Africa until August 10 over the security fears.
The State Department also announced a global travel alert, warning that al Qaeda or its allies might target either US government or private American interests.
In a statement, spokeswoman Jen Psaki said: "This is not an indication of a new threat stream, merely an indication of our commitment to exercise caution and take appropriate steps to protect our employees including local employees and visitors to our facilities."
It said diplomatic posts in Abu Dhabi, Amman, Cairo, Riyadh, Dhahran, Jeddah, Doha, Dubai, Kuwait, Manama, Muscat, Sanaa, Tripoli, Antanarivo, Bujumbura, Djibouti, Khartoum, Kigali, and Port Louis would be closed from Monday through to Saturday of the coming week.
Those reopening for normal operations on Monday included Dhaka, Algiers, Nouakchott, Kabul, Herat, Mazar el Sharif, Baghdad, Basrah, and Erbil.
The extension came as security forces closed roads, put up extra blast walls and increased patrols on Sunday near some of the 22 diplomatic missions ordered to close.