ISLAMABAD, Nov 27: Pakis-tan stepped up border security to prevent Osama bin Laden from slipping across the border from Afghanistan to evade a US manhunt, a senior government official said on Tuesday.

“The border has been sealed. The border levies (security forces) have been put on a 24-hour-surveillance alert and tribal leaders have been asked to prevent people from crossing illegally,” said the official, who asked not to be named.

Osama may be running out of hiding places as anti-Taliban forces grab more territory and US marines deploy at a desert airstrip in southern Afghanis-tan.

President Pervez Musharraf said on state television on Monday, that the government had taken strict measures to foil any attempt by Osama to enter Pakistan.

The official said the porous 2,240km border with Afghanistan was being tightly monitored with the help of tribal elders whom the government had asked to keep watch for Osama.

“We have not left any possibility open that Osama can sneak in,” he added.

Border officials said the extra security meant that all crossings, whether formal border posts or informal routes frequented by smugglers or refugees, were being watched. But a source close to religious groups said it was impossible for the authorities to seal the border.

“If Osama wants to come, he can smuggle himself in, though I doubt he will ever do that,” said the source.—Reuters