LONDON — News of a thwarted plot to down trans-Atlantic airliners sent a shiver of anxiety through Britain's Muslim community Thursday.

Muslim men accustomed to nervous looks from passers-by after last year's transit bombings noticed they were attracting them again. Some said they worried about a spike in hate crimes and job discrimination.

There was no confirmed word about the religious or ethnic background of those arrested, although a top French official described them as originating from predominantly Muslim Pakistan. Police said only that they were working with Britain's large South Asian community.

Three of the four suicide bombers who struck London's transit system in July 2005 were Britons of Pakistani origin, and many Muslims feared their community would be held responsible this time.

Monirul Sardar, 33, said that after the transit bombings and the Sept. 11 attacks on America, a neighbor left duck droppings on his parked car.

"Tonight I've got to watch out," he said.

Sardar, a Briton of Bangladeshi origin who runs an east London travel agency, said he'd noticed his bushy beard drawing stares after every major terror attack in recent years.

"It's started up again," he said. "People are afraid of me, mostly. ... If it's an old man, a lady in a hijab (head covering), they'll pick on them."

Harris Bokhari, a spokesman for the Muslim Association of Britain, said the group was asking mosques to urge worshippers to report any racial attacks.

But he said Muslims had demonstrated after the Sept. 11 attacks and the London bombings that they would not let such trouble stop them from participating in British life.

The Muslim community's relationship with police has been fraught in recent months, and some said they were waiting to see what evidence police would produce of the alleged bomb plot.

"They've arrested people, but let's see what they find from them," said Maj Ali, 27, who works at a northeast London restaurant near a home police were searching as part of their terror investigation.

"They didn't find nothing," he recalled of a June raid in which officers shot a man in the shoulder in his east London home during a search for the makings of a chemical bomb.

The man and his brother were arrested but later freed without charge. That raid and the fatal subway shooting last year of an innocent Brazilian man mistaken for a terrorist infuriated many Muslims.

"Was this (airline bomb plot) information really accurate or not from the police in terms of its intelligence?" Bokhari asked. "We need to be aware how these people were arrested."

Near the East London Mosque in the capital's Whitechapel neighborhood, home to a large Muslim population, several people said they feared the terror plot allegations might spark fresh antagonism against them.

"People forget things really easily," Sardar said. "This brings it all back again."

Associated Press Writer Katie Fretland contributed to this story.