Saudi authorities have detained an American and a Briton for unspecified reasons, diplomats said Saturday. A Saudi newspaper said the American was the brother of two men convicted in the United States of conspiring to aid the Al Qaeda (search) terrorist network.

A U.S. diplomat at the consulate in the Red Sea port of Jiddah confirmed to The Associated Press that an American citizen had been picked up there by the Saudis, "but we don't know why."

The diplomat, who insisted on anonymity, refused to name the American. Saudi authorities were not immediately available for comment.

The English-language Arab News daily identified the American as Abdullatif Ibrahim Bilal, brother of Ahmed and Muhammad Bilal (search), members of a group in Oregon known as the Portland Seven (search) who were accused of plotting to join the Taliban (search) in 2001 to fight a holy war against the U.S. forces in Afghanistan.

In September, the Bilal brothers pleaded guilty to charges of conspiring to help Al Qaeda and the Taliban and to firearms charges, in exchange for having the main charge of conspiracy to wage war against the United States dismissed. They are awaiting sentencing and face up to 14 years in federal prison.

Arab News quoted Bilal's father -- without giving his name -- as saying his son has been picked up, but he had no idea why.

British Embassy spokesman Barry Peach identified the Briton as David Heaton, a convert to Islam.

Peach said Heaton is in Saudi detention. He said officials from the British consulate in Jiddah visited Heaton on Thursday.

"We have contacted his next of kin, and we are seeking reasons for his detention from the Saudi authorities," he said.

"Saudis have confirmed that he has not been charged yet," Peach added.

It was not clear whether the arrests are part of the nationwide security crackdown the government launched following the May 12 attacks on three Western residential compounds and that has intensified after another attack on a residential compound Nov. 8.