Updated

A key Al Qaeda (search) operative suspected of authoring surveillance documents that sparked terror alerts in the United States was among 13 terror suspects arrested in Britain, an official said. The operative is believed to have been in the United States in 2000.

The documents of surveillance of five U.S. financial institutions were found on the computers of two accused members of Usama bin Laden's terror network arrested in Pakistan last month. Pakistani intelligence officials told The Associated Press the computers also held images of London's Heathrow Airport (search) and that this information was passed to British officials.

The revelations draw a link between two major sweeps against suspected Al Qaeda networks in Pakistan (search) and Britain — as well as the alerts announced Sunday in New York, New Jersey and Washington.

At least 20 people have been detained in Pakistan in the past month, and Britain is holding 12 men from raids on Tuesday after releasing one person. British police on Thursday announced the arrest of another man, wanted in the United States for allegedly helping finance terrorist activity.

Among the 12 held in Britain was a senior Al Qaeda member, known as Abu Eisa al-Hindi (search) or Abu Musa al-Hindi, who the official said is suspected of having written the surveillance reports detailing security, construction and other features of the five U.S. financial buildings.

The official called al-Hindi "a key Al Qaeda operative."

Al-Hindi is believed to have been in the United States in 2000.

Much of the information that led to the U.S. terror alerts was at least several years old, some of it preceding the Sept. 11, 2001, attacks, U.S. officials have acknowledged, though some of it may have been updated as recently as January. A counterterrorism official, speaking on the condition of anonymity earlier this week, said the surveillance reports and other material showed fluency in English, indicating the author spent significant time in the West.

The terror alert concerned the Citigroup Center Building and New York Stock Exchange, the Prudential Building in Newark, and the International Monetary Fund and World bank in Washington.

It was prompted by maps, photographs and other details of possible U.S. and British targets that were found on computers belonging to Ahmed Khalfan Ghailani (search) — a Tanzanian indicted for his role in the 1998 bombings of U.S. embassies in East Africa — and a Pakistani computer expert, Mohammed Naeem Noor Khan, said two Pakistani officials, who spoke on condition of anonymity.

Khan was arrested by Pakistani forces in Lahore on July 13, followed by Ghailani's arrest on July 25. Both men speak fluent English.

British police also said Thursday they had arrested a British man, Babar Ahmad (search), wanted on terrorism charges in a warrant issued by a federal prosecutor in Connecticut on charges he tried to raise funds for "acts of terrorism in Chechnya and Afghanistan" from 1998 through 2003.

Ahmad — a cousin of Khan — used U.S.-based Web sites to recruit fighters and raise support for Taliban forces in Afghanistan and had a document on battle group plans for U.S. Navy vessels in the Persian Gulf, lawyers representing the United States said Friday at Ahmad's first court appearance in London.