New York is on high alert as world leaders begin arriving for the United Nations general assembly.

Security in the city has been elevated since US intelligence agencies received information about “specific and credible” threats of a terrorist attack planned to mark the 10th anniversary of the September 11 attacks.

The annual UN general assembly opened its 66th session on Tuesday, but the main events, including speeches by leaders, start on Monday at the UN headquarters on Manhattan’s east side.

The meeting coincides with the Clinton Global Initiative, former US president Bill Clinton’s annual philanthropic summit, which attracts business executives, celebrities and heads of non-profit organisations.

The New York Police Department said it was working with the secret service and State Department to protect 130 heads of state and co-ordinate 220 motorcades.

Midtown hotels, including the Waldorf-Astoria and the Intercontinental-The Barclay have stepped up security for high-profile guests, including installing concrete barriers on sidewalks and streets.

“The most recent threat has not been resolved and there are still some questions,” said Paul Browne, deputy commissioner of the NYPD. “Going into next week, the security posture will increase again because of the UNGA, mainly in the vicinity of the UN headquarters and hotels where the heads of state will reside. But nothing as yet has told us that the UNGA is the target of a threat”.

Extra officers in the streets, dedicated traffic lanes, fortified motorcades for high-risk heads of state and divers checking for explosives in the East River are some of the measures taken each year. Additional security measures, such as vehicle checkpoints and more frequent bag searches for subway commuters that were imposed over the September 11 weekend, might also be implemented.

George Ogilvie, spokesperson for the secret service said: “We always operate at the highest security level and we always co-ordinate with local and state partners such as the NYPD”. Mr Ogilvie said he could not comment on any security measures being taken.

Last week, in addition to thousands of extra police officers and surveillance cameras, the NYPD prepared to respond to potential threats for the anniversary with quick-strike reaction forces including officers in heavy armour, bomb squad technicians, hostage negotiators and highway patrol escorts on standby.

Several groups plan protests outside the UN headquarters over causes including Palestinian statehood, Taiwanese membership in the U N and Tibet.

Separately, the NYPD closed off sections of Wall Street on Saturday and Sunday, after thousands gathered to demonstrate their disillusionment with the country’s financial system.

(Source: Financial Times)