Intelligence reports have raised fears of a terrorist attack in Kenya (search), possibly on embassies and residences of foreign officials, Western officials said Friday.

Intercepted communications among Al Qaeda (search) operatives in eastern Africa and other unspecified intelligence indicate terrorists are plotting an attack in Nairobi (search), a U.S. official said on condition of anonymity.

The British government warned its citizens Friday to be on guard against "a clear terrorist threat" in six eastern African countries — Uganda, Ethiopia, Tanzania, Somalia, Eritrea and Djibouti. However, it did not advise British nationals to avoid all nonessential travel there, as they have been told about Kenya.

Both the United States and Britain, along with other European countries, have warned in recent days of a possible terrorist attack in Kenya. But none had previously specified the nature of the intelligence leading to the warnings, or that embassies or residences could be targeted.

British High Commissioner Edward Clay confirmed there has been a "wave" of intelligence in recent weeks pointing to an attack. Britain on Thursday suspended flights between Nairobi and London because of a threat to British jets, and warned against unnecessary travel to Kenya. The United States also said travelers should postpone trips there.

Britain has linked the threat to Monday's Al Qaeda-connected suicide bombings in the Saudi capital, Riyadh (search), that killed 34 people, including eight Americans.

It said the warning Thursday was also linked to reports that Fazul Abdullah Mohammed, an alleged Al Qaeda operative suspected in the 1998 U.S. embassy bombings in Kenya and Tanzania and the Nov. 28 attacks on the Kenyan coast, reportedly resurfaced in the port of Mombasa.

Along with increased security around foreign embassies, the Kenyan government is beefing up protection around airports, monitoring flight paths and stepping up patrols, especially in Nairobi National Park, which is adjacent to the airport, said National Security Minister Christopher Murangaru.

Mohammed and others appear to have regrouped after the November attack on the Kenyan coast, the U.S. official said.

Another team is believed to be in Mogadishu, the capital of neighboring Somalia, a chaotic country without a central government, the U.S. official said from Washington.

The two teams are in contact with each other and Al Qaeda operatives in the Middle East and Pakistan, the U.S. official said.

Also of concern are upscale town house complexes that dot Nairobi. They are well guarded against the city's rampant crime, but it's unclear whether they could repel a coordinated terrorist attack.

A Western official, who spoke on condition of anonymity, said the Kenyans are eager to help combat terrorism. But since a new government was elected in December, some longtime security officials have moved on, leaving the job of fighting terrorism in relatively inexperienced hands, the official said.

The U.S. Embassy and British High Commission in Nairobi were open Friday.

In the Nov. 28 attack, assailants tried to shoot down a chartered Israeli jet with shoulder-fired missiles as it was taking off from Mombasa's airport. The missiles narrowly missed.

Within a few minutes of that attack, suicide bombers detonated a car packed with explosives outside a beachfront hotel popular with Israelis, killing 11 Kenyans and three Israelis.

Mohammed is believed to have fled to neighboring Somalia after the hotel bombing. He is reported to have trained in Afghanistan with Osama bin Laden.

The FBI has indicted Mohammed in the 1998 U.S. embassy bombings in Nairobi and Dar es Salaam, Tanzania, that killed 231 people, including 12 Americans.