Intelligence agents arrested two British nationals of Pakistani origin who provided information on the terror plot aimed at blowing up U.S.-bound passenger jets from Britain, a senior government official said Friday. One suspect was arrested in the eastern city of Lahore and the second was picked up in Karachi, Pakistan's main port on the Arabian Sea, the official was quoted as saying by the Associated Press. «Our intelligence agencies made the arrests about one week ago,» he said. Pakistan's government said Thursday it had played «a very important role» in uncovering the plot. Interior Minister Aftab Khan Sherpao said Friday that Pakistan had made some arrests, but refused to give details. Several Pakistani intelligence officials also confirmed the arrest of a third suspect in the eastern city of Faisalabad four or five days ago, but could provide no details on the suspect's identity or nationality. They said they expected more arrests would follow. British authorities arrested 24 people Thursday based partly on intelligence from Pakistan. The suspects were believed to be mainly British Muslims, at least some of Pakistani ancestry. On Friday, Pakistan stepped up security at airports, preventing hand-carried luggage on all flights, but state carrier Pakistan International Airways reported no delays and said a flight would depart on schedule for London's Heathrow airport around midday.