Canada's foreign affairs ministry won't have an answer for at least a day about the citizenship of a terrorism suspect arrested in Pakistan.

There are unconfirmed reports that Mohammad Naeem Noor Khan holds Canadian citizenship.

He was arrested July 13 and may have provided the intelligence that led to a terror alert flap in the United States last Monday. Security levels for five financial institutions were raised as a result.

Authorities say he has been co-operating, even sending e-mails to his al Qaeda contacts while in custody.

Reynald Doiron, a spokesman for Foreign Affairs, said time zone differences mean an answer about Khan won't be available until Sunday.

Khan's father lives in Pakistan. He hasn't spoke to his son in years.

Other suspects

One major arrest made was Ahmed Khalfan Ghailani, who was arrested July 25 -- although the fact wasn't made public until July 29.

He is wanted in connection with the bombings of U.S. embassies in Kenya and Tanzania that left 224 results.

There was a $25 million US bounty on Ghailani's head. Khan provided information that helped authorities find Ghailani's hide-out in Gjurat.

Pakistani security officials said Saturday they were searching for two associates of Ghailani: Abu Farj, a Libyan citizen, and Hamza, an Egyptian.

Khan is believed to have provided information about the two to Pakistani authorities. Ghailani is also reportedly co-operating.

One possible target that Khan had information on was London's Heathrow Airport, the busiest in Europe.

On Tuesday, British authorities arrested 13 suspects, including a man known as Abu Musa al-Hindi. He is believed to be a senior al Qaeda operative who had been planning an attack on the airport.