LONDON - "Those who cure you are going to kill you."

That, a British priest said Wednesday, was the cryptic warning made to him in Jordan by a purported al-Qaida chief months before the failed car bombings in London and Glasgow that have been linked to a group of foreign Muslims working as doctors in Britain.

Britain's Prime Minister Gordon Brown speaks in the House of Commons, London, Wednesday, July 4, 2007, during Prime Minister's Questions. [AP]

British authorities have said the attacks bore the hallmarks of an al-Qaida operation, but security officials say investigators are still trying to determine whether there was any direct link between the alleged plotters and an outside mastermind.

Canon Andrew White, a senior Anglican priest who works in Baghdad, said he met the man privately with a translator and sheik after holding talks with Sunni Muslim tribal and religious leaders April 18 in the Jordanian capital, Amman. He meets regularly with extremists in an attempt to calm Iraq's sectarian violence.

He said religious leaders told him the man was an al-Qaida leader who traveled from Syria to the meeting. The man, an educated Iraqi in his 40s and dressed in Western clothes, warned of attacks on Britain and the United States, White said.

"It was like meeting the devil," he told The Associated Press in a telephone interview from Baghdad. "He talked of destroying Britain and the United States and then said, 'Those who cure you are going to kill you.'"

White, who runs Baghdad's only Anglican parish and has been involved in several hostage negotiations in Iraq, said he did not understand the threat's significance at the time. He said he passed the general threat along to Britain's Foreign Office, but did not mention the comment that could be interpreted as hinting at the involvement of doctors in a terror plot.

Then came the news that six physicians were among the eight suspects detained in the failed attacks in Britain.

"As soon as I heard many of the suspects were doctors I remembered those words," he said. "I work with a lot of people who are not necessarily good people. It becomes very difficult to distinguish what threat is real and what is not."

White said he gave the man's identity to the Foreign Office but would not say publicly what it was. He also said he gave the same details to American authorities in Baghdad.

A spokesman for the Foreign Office, who spoke on condition of anonymity in line with government policy, denied White relayed the man's identify but confirmed he reported his meeting with the alleged al-Qaida leader.

He also said that White did not pass on the reference alluding to medical practitioners and that because his information was vague it "didn't really merit further analysis." But White's report has now been given to British police in their investigation, the spokesman said.

Prime Minister Gordon Brown, meanwhile, announced that Britain will increase its scrutiny of foreigners recruited for their skills, including doctors coming to work for the National Health Service, which employed all eight suspects in the failed car bombings.

"We'll expand the background checks that have been done where there are highly skilled migrant workers coming into this country," Brown told the House of Commons in his first appearance at the weekly prime minister's questions.

The government also lowered its terrorism threat level one step to "severe" from "critical" - the highest on a five-point scale. Officials said Tuesday that investigators believe the main plotters had been rounded up, though others on the periphery were being hunted.

The reduction "does not mean the overall threat has gone away - there remains a serious and real threat against the United Kingdom and I would again ask that the public remain vigilant," Home Secretary Jacqui Smith said in a statement.

A U.S.-based intelligence monitoring group said Wednesday that it obtained a copy of a video intended for posting on militant Internet sites in which al-Qaida's No. 2 leader urges Muslims to unite in a holy war against the West but doesn't mention the bombing attempts in Britain.

It was not possible to determine from the transcript released by the group SITE whether the tape of Ayman al-Zawahri was recorded before the attacks.

Several of the arrested men in the British plot were on a watch list compiled by the domestic intelligence agency MI5, a British government security official said, indicating their identities previously had been logged by agents. The official did not say why they were put on the watch list.

"Some, but not all, have turned up in a check of the databases, but they are not linked to any previous incident," the security official said, speaking on condition of anonymity because of the sensitivity of the material.

The official said Britain's security services are watching about 1,600 people and have details logged about hundreds more.

The Evening Standard said one suspect on the list had posted a comment on an Internet chat room condemning Danish cartoons portraying the Prophet Muhammad in a derogatory way. The newspaper, which cited unidentified intelligence sources for the information, did not say which suspect.

The Times of London said one of the eight people in custody, Iraqi-born physician Bilal Abdulla, reportedly had links to radical Islamic groups and several others were linked to extremist radicals listed on the MI5 database.

Abdulla was a passenger in the Jeep that smashed into Glasgow's airport. Investigators believe the same men who parked two explosives-laden Mercedes cars in London may have also driven the blazing SUV in Glasgow, officials say.

Shiraz Maher, a former member of a radical Islamic group, said he knew Abdulla at Cambridge University.

"He was certainly very angry about what was happening in Iraq. ... He supported the insurgency in Iraq. He actively cheered the deaths of British and American troops in Iraq," Maher told BBC television's "Newsnight."

He said Abdulla berated a Muslim roommate for not being devout enough, showing him a beheading video and warning that could happen to him. Maher said Abdulla also claimed to have a number of videos of the then-leader of al-Qaida in Iraq, Abu Musab al-Zarqawi, who was killed by a U.S. airstrike last year.

Abdulla had been disciplined by his employers at the Royal Alexandra Hospital, outside Glasgow, for spending too much time on the Internet, according to hospital staff, suggesting the plot may have been planned in cyberspace.

Police seized several computers from hospitals in Glasgow, Stoke-on-Kent and Liverpool.

British Broadcasting Corp., citing unidentified sources, said police in Scotland had identified a house rented by one of the suspects arrested in Glasgow as a potential bomb factory. Police could not comment on the report.

While information held on the MI5 database did not alert authorities to the attacks, it did help police to round up suspects quickly, the government security official said.

The eight suspects include one doctor from Iraq and two from India. Also in custody are a physician from Lebanon and a Jordanian doctor and his medical assistant wife. Another doctor and a medical student are thought to be from the Middle East, possibly Saudi Arabia.

No one has yet been charged in the plot.

The family of one suspect - Muhammad Haneef, a 27-year-old doctor from India arrested Monday in Australia - professed his innocence. Haneef worked in 2005 at Halton Hospital near Liverpool in northern England, hospital spokesman Mark Shone has said.

"He is innocent," Qurat-ul-ain, Haneef's mother, told AP in the southern Indian city of Bangalore.

Another Indian national arrested in Liverpool was Sabeel Ahmed, a 26-year-old doctor whose family in Bangalore said Wednesday that he was related to Haneef but did not say how.

"Both these boys are just caught in between," his mother, Zakia Ahmed, who also is a doctor, said in front of her home in an upscale neighborhood about 7.5 miles from Haneef's home.