In November a suicide attack near Mombasa killed 15

The German Government has advised its nationals to avoid all non-essential travel to Kenya, Tanzania and Djibouti.

The government said it had issued the advice "because of signs of possible terrorist attacks which could focus on foreign and tourist areas" in these countries.

Meanwhile, the Israeli national airline, El Al, has suspended all flights to Kenya for the same security reasons.

Last November, two ground-to-air missiles were fired at an Israeli plane carrying tourists taking off from Mombasa airport.

It is the second foreign national airline to do so after the UK Government announced that British Airways had cancelled its flights to Kenya last week.

The Kenyan Government said the move was unjustified and a panic measure.

The decision followed a warning from the Kenyan security forces who said they believed a leading al-Qaeda suspect, named as Fazul Abdullah Mohammed, had returned to Kenya.

He is accused by the FBI of involvement in the bombing of American embassies in East Africa in 1998.

Profile: Africa's key suspect Al-Qaeda 'threat remains' Brits in Kenya divided

The UK Foreign Office has warned of a "clear terrorist threat" in Kenya and six other East African countries: Djibouti, Eritrea, Ethiopia, Somalia, Tanzania and Uganda.

The US Government has already warned Americans to postpone non-essential trips to Kenya.

The International Press Institute (IPI) ir reported on Monday to have cancelled its annual congress due to be held in the Kenyan capital next month after the recent warnings.

The recent measures are the latest setback to hit the country's tourist industry, which is one of the country's main foreign exchange earners