The co-owner of a catering company that organised events for the US Embassy is among six men detained by Pakistan for allegedly helping the failed Times Square bombing suspect, a senior Pakistani intelligence official said.

In a statement on its website, the US Embassy warned the catering company was suspected of ties to terrorist groups and said American diplomats had been instructed to stop using the firm.

Like Faisal Shahzad, the Pakistani-American accused over the failed New York bombing, the six Pakistani detainees were all members of their country's urban elite, including several who were educated in the US.

One was a former major who bought his way out of the army because of a "disagreement with its policies", the Pakistani official said.

The suspects were part of a loose network motivated by hatred of America and the West and one of the men often travelled to the tribal areas close to the Afghan border where US officials have said Shahzad received explosives training under the Pakistani Taliban, the official said.

At least two allegedly helped Shahzad with funding, the official and another Pakistani security officer said, although the exact nature of their link to the Times Square bombing suspect was still being investigated.

The co-owner of the Hanif Rajput Catering Service, Salman Ashraf Khan, was recruited because two other suspects "wanted him to help bomb a big gathering of foreigners" whose event his company was catering, the Pakistani intelligence officer said.

He said a US tip led to the first arrest - a computer engineer, Shoaib Mughal, who runs a large computer dealership in Islamabad.

Mughal is accused of telephoning Shahzad soon after the failed May 1 bombing in New York's Times Square and urging him to return to Pakistan. He also visited the Afghan border region several times to meet with top Taliban commanders, including Hakimullah Mehsud, and give them money, the official said.

Several of the suspects arrested in Pakistan were educated in the US.

A biography on the website of the Hanif Rajput Catering Service said company co-owner Salman Ashraf Khan attended college in Houston, Texas before returning home to help run his family's business. The company founder is his father, Rana Ashraf Khan.

"I am shocked at what I am hearing," Rana Ashraf Khan said.

He said his son was a devout Muslim who went to the US in 1997, first to study hotel management in Florida and then to Houston, where he majored in computer science.

"If there is any suspicion about my son of some links, put him on trial, but do not blame my company for involvement in this kind of heinous crime," he said.

The catering company works for foreign embassies and many of Pakistan's wealthiest companies and individuals. The website features inspirational quotes by basketball star Larry Bird and poet John Keats.

The US Embassy warning about the company was e-mailed to all Americans registered with the embassy under rules that require threat information to be shared with the wider American community, said Rick Snelsire, an embassy spokesman.

All but one of the six suspects were picked up in the capital, Islamabad, said the intelligence official, who was involved in the interrogations.

He said one suspect had an MBA from the United States and knew Shahzad from his time there. He was working for a mobile phone service provider in Pakistan at the time of his arrest.