The US embassy in Nairobi is temporarily closed

Kenya banned flights to and from Somalia because of an unspecified terror threat.

But Somali leader Abdulkassim Salat Hassan, head of the Transitional National Government, denied there was any such danger.

"There are no terrorist cells in Somalia, but our credibility is being dented by false accusations placed by some Somali warlords," he said.

The Kenyan decision followed Friday's warning of a possible imminent attack on the United States embassy in Nairobi.

Kenyan authorities dismissed the US assessment as "wrong and misleading".

Narcotic flights

Kenya has in the past accused Somalia of being responsible for the infiltration of arms into the country.

The embassy was only recently reopened to the public after an attack in 1998, which killed over 200 people, blamed on the al-Qaeda organisation.

The US administration has described the Horn of Africa as being a safe haven for extremist groups.

The flight ban imposed by Kenya has chiefly affected traders who fly tons of the mildly narcotic leaf, khat, into Somalia every day.

'Safer than New York'

In recent days, Kenyan police have been involved in a large security operation in a Nairobi suburb which is home to thousands of Somali refugees.

More than 40 people in Eastleigh have been detained - many thought to be suspected criminals and illegal aliens.

Tons of khat are flown into Somalia every day

The BBC's Andrew Harding in Nairobi says Kenyan authorities are keen to show that they are pulling their weight in the US war against terror.

They have been stung by American criticism that no one has yet been charged in connection with last November's co-ordinated attacks against an Israeli plane and hotel near the Kenyan coastal resort of Mombasa.

For the past month, the US, Britain and Germany have warned tourists not to visit Kenya because of fears of a new al-Qaeda strike.

The Kenyan Government has urged governments to relax their travel advisories, complaining that the local tourism industry is being devastated.

Kenyan National Security Minister Chris Murungaru told the French AFP news agency on Saturday that the dangers of a fresh attack had been exaggerated by US officials.

"They should know that New York is not any safer than Nairobi," he told AFP.