A British court on Thursday ordered the first person to be charged in connection with the failed July 21 bomb attacks in Britain to remain in custody. Thousands of police officers patrolled London's streets and sprawling subway system, four weeks after four bombs killed 56 people.

Also Thursday, British police probing the failed bombings said they have charged two women under anti-terror laws.

The first person charged, Ismael Abdurahman (search), 23, from southeast London, spoke only to confirm his name and age during a 10-minute hearing in Bow Street Magistrate's Court before being led to jail.

He faces charges of withholding information that helped suspected subway bomber Hamdi Issac (search) initially avoid capture. Issac was later detained in Rome and is being held on international terrorism charges. Italian court officials on Thursday said an extradition hearing would be held Aug. 17.

Abdurahman's attorney, Anne Faul, said her client was innocent. "The defendant will be and is vigorously contesting the charges," she said. "He has no involvement in terrorist activity whatsoever."

The massive security operation Thursday involving 6,000 officers was intended to reassure the public four weeks after the July 7 attacks and two weeks after the failed July 21 attacks.

Officials stressed there was no specific intelligence of a third attack, but undercover police were mingling with passengers, and officers were armed with machine guns and pistols. Police helicopters hovered above while traffic was heavier than normal.

"It's a little bit eerie," said Rosalyn Cooper, 23, before she got on the Tube. "You can't help thinking about when it will happen again."

On the Northern line, authorities told commuters to watch out for suspicious activity.

The New York City police said the July 7 suicide bombers cooked up their explosives with items like hydrogen peroxide, suggesting that the ingredients could have been bought at a hardware or beauty supply store.

Details from the July 7 London bombings emerged Wednesday at an unusually wide-ranging briefing given by the New York Police Department to city business leaders.

Meanwhile, London transport authorities on Thursday opened the Piccadilly Line, the subway line that was worst-hit in the July 7 attacks, easing disruption on the network that carries some 3 million passengers a day.

"The return of the Piccadilly line is a major step as the Underground and London get back to normal," London Underground Managing Director Tim O'Toole said.

Transport for London, the public body that runs the Underground, said passenger numbers had dipped by 30 percent on weekends and by between 5 percent and 15 percent on weekdays since July 7.

Meanwhile, some $14.2 million has been raised through charitable donations to help victims of the July 7 attacks. The London Bombings Relief Charitable Fund said bereaved relatives would receive payments of $8,900, while people who were injured and spent a night in hospital will receive $5,300.

The Piccadilly Line is one of the busiest sections of London's subway system. It had been partly suspended since a bomb exploded on a train in the July 7 attacks, killing 21 commuters — a closure that caused significant disruption on the network.