ISLAMABAD/KARACHI, 12 August 2006 — Pakistan said yesterday it had stepped up airport security after Britain foiled alleged plans to blow up US-bound flights, with a number of suspects arrested in Pakistan.

“All the airports have been put on high alert,” an Interior Ministry official said, adding that security levels had been raised on Thursday immediately after the plot was revealed.

Extra armed police stood guard at major airports in Karachi, Islamabad and Lahore while passengers were subject to hand baggage restrictions and extra screening.

“Passengers were not allowed to carry hand luggage in all the foreign flights,” said a security official at Karachi’s Jinnah International Airport.

He said the ministry had directed all airlines to make sure that the passengers could only carry their belongings in transparent bags along with them while traveling.

No flights to Britain or the United States were canceled due to the security alert but passengers have been advised to reach the airport at least three hours before normal for security checks, he said.

Vehicles entering airport car parks were being thoroughly checked. Pakistan, a key US ally, is already on alert for its Independence Day celebrations early next week.

Air travelers around the globe faced delays and massively heightened security measures Friday after Britain said it had detained 24 suspects who allegedly plotted to detonate bombs on transatlantic airliners.

Pakistani authorities said yesterday they had arrested at least seven people including two British nationals of Pakistani origin who played key roles in the bomb plot.

The arrests were made in the eastern city of Lahore and in Karachi, the official said. Two were Britons arrested a week ago and had provided information about the plot during interrogation, he said.

The five Pakistanis were arrested on suspicion that they served as their local “facilitators,” the official said. At least three of those arrested were linked to Al-Qaeda, a security official said. It wasn’t clear when they’d been detained. An official at the British High Commission in Islamabad could not confirm the arrests of the Britons, and referred questions to Pakistan’s government.

Pakistan’s government said Thursday it had played “a very important role” in uncovering the plot — allegedly to bring down as many as 10 jetliners in a nearly simultaneous strike that US officials say was suggestive of an Al-Qaeda operation.

Foreign Ministry spokeswoman Tasnim Aslam yesterday said some arrests were made in Pakistan but refused to give details. “The investigation is going on. We are not talking about their identities,” she said.