A Treasury statement read: "On the advice of the police and security services, the Treasury has instructed the Bank of England to issue notices to effect a freeze of the assets of a number of individuals arrested in yesterday's operations."

Twenty-four people were arrested on Thursday in police raids in London, the south of England and Birmingham after a police investigation into a plot to blow up several trans-Atlantic airliners.

The bank released the following names and posted them on its website: Abdula Ahmed Ali, Cossor Ali, Shazad Khuram Ali, Nabeel Hussain, Tanvir Hussain, Umair Hussain, Umar Islam, Waseem Kayani, Assan Abdullah Khan, Waheed Arafat Khan, Osman Adam Khatib, Abdul Muneem Patel, Tayib Rauf, Muhammed Usman Saddique, Assad Sarwar, Ibrahim Savant, Amin Asmin Tariq, Shamin Mohammed Uddin and Waheed Zaman.

The oldest person on the list, Shamin Mohammed Uddin, is 35. The youngest, Abdul Muneem Patel, is 17. Most of those named in the list were London residents.

The police have been given permission to hold 22 of the suspects without charge until next Wednesday. One man was released without charge while a decision on the remaining person will be taken at a magistrates' court hearing on Monday.

British police gave no details of the people they had arrested, but the US homeland security department said all were British citizens.

Pakistan said it played a role in thwarting the suspected plot and had arrested an undisclosed number of people. A senior government official, speaking on condition of anonymity, said two of the men arrested were British nationals of Pakistani origin.

They were arrested in the southern city of Karachi and in Lahore last week.

Ongoing impact

In Britain, new security measures remained in place at airports on Friday. Airports were jammed on Thursday and scores of flights were cancelled.

British Airways said it expected to cancel about 40% of its short-haul and 25% of its long-haul flights from London's Heathrow airport on Friday.

In Britain, all hand luggage was banned and passengers were allowed on board with only a single clear plastic bag containing items from an official list. In the US, authorities banned liquids and gels from bags being carried on to aircraft.

Airport authorities told people to stay home if they could.

News of the suspected plot affected financial markets. Shares in European airlines fell. The pound fell against the dollar and the euro. Oil fell to below $76 a barrel on fears the security threat might slow growth worldwide and cut oil demand.