LONDON —  Three men have been charged with possessing materials that could be used to carry out terrorist acts, police said Saturday.

Scotland Yard said the suspects were charged with possessing materials for the "preparation, instigation or commission" of terrorist acts.

Rabah Chekat-Bais, 21, Rabah Kadris, in his mid 30s and Karim Kadouri, 33 — all of no fixed address — appeared in court earlier this week. They were being held in custody until their next court appearance.

The Sunday Times newspaper reported that the men had been plotting to release gas, possibly cyanide, on the London subway system. But police would not comment on the newspaper report.

The Home Office confirmed the three arrests but said it could not comment on an active court case.

Last week Prime Minister Tony Blair said barely a day went by without new intelligence about a threat to British interests — some reliable but some likely misinformation or gossip.

He advised British people to be vigilant against terrorism, but not allow fear to distort normal life.

"If a terrorist thought that all he had to do to shut down the travel industry, for example, was to issue a threat against our airports, we really would be conceding defeat in the war against terrorism," Blair told the annual Lord Mayor's banquet in London's financial district.