Police said today that the security threat at the US embassy here which has forced its indefinite closure was over suspicions that several foreign men were surveilling the mission.

The police chief for Kuala Lumpur, Mustafa Abdullah, said a staff member at the embassy had reported seeing the men, including one carrying a camera, loitering outside the mission on Thursday.

The men were caught on the embassy's close-circuit television system and police were investigating the incident after the embassy lodged a report yesterday, he said.

"They lodged a police report yesterday saying that they saw somebody carrying a camera in front of the embassy, so they believe these people are trying to take photographs of the embassy," Mustafa told AFP .

"They presume these people were trying to do harm to the embassy," he said.

Foreign men

The US embassy shut abruptly on yesterday morning, citing an unspecified threat which it said was directed at the mission, rather than private American interests in the country.

"The embassy will close effective today ... until further notice due to a security threat to the embassy," it said in a statement.

Mustafa said the embassy's police report described the men as foreigners, although he could not elaborate further.

"According to them it was a few male foreigners ... one believed to be carrying a camera," he said.

"They were loitering somewhere in the vicinity of the American embassy."

Mustafa said police had viewed the TV footage and were trying to establish the identity of the people, but downplayed the incident.

"To us it's not a threat. It's a misunderstanding," he said.

"They could be tourists loafing around the area carrying cameras. Kuala Lumpur has a lot of tourists carrying cameras."

Security tightened

But Mustafa said police would continue heightened security measures around the embassy, a complex in central Kuala Lumpur situated on one of the city's main thoroughfares.

"We have extra police patrols and we have stationed our officers outside of the embassy," he said.

He also said more than 1,000 police officers would be deployed around Kuala Lumpur for New Year's Eve celebrations, which are expected to draw hundreds of thousands of people to the city.

US embassy spokeswoman Kathryn Taylor, who has declined to give details of the threat, has said the situation would be reassessed on Monday, when the mission was already closed for a public holiday, and decide whether to reopen on Tuesday.

Security threats against diplomatic missions happen frequently in Malaysia, although there have been no terrorist attacks on Malaysian soil.