There was no immediate claim of responsibility for Tuesday's
blast.
Sources said the bomb was stored in a 33-pound (15 kilo) gas
canister, similar to those used by Algerian Muslim
fundamentalists who claimed responsibility for most of last
year's bombings.
Officials said the blast occurred at 6:05 p.m. (12:05 p.m.
EST/1705 GMT) at the Port-Royal station, a ground-level
station on the RER regional line used by thousands of
commuters in and out of the French capital. RER lines run
both above and under ground.
Anti-terrorist plan reactivated
"There was an explosive device that was put in a subway car,"
French Prime Minister Alain Juppe told reporters. He said
officials put back into effect an emergency vigilance plan
activated after France was hit last year by eight subway
bombings that killed eight people and wounded 160.
The security plan, called "Vigipirate," involves police and
army patrols in sensitive public areas and spot checks across
the country.
Interior Minister Jean-Louis Debre said France was tightening
its borders as a precaution, and train stations and airports
across France were on alert and increasing security.
President Jacques Chirac condemned what he called "these
unacceptable acts, these barbaric acts that always attack
innocent people."
"The government and I are determined to fight against
terrorism in all its forms. Nothing will be neglected,"
Chirac said in a news conference outside the presidential
Elysee Palace.
CNN's Peter Humi reports from Paris
(208K/18 sec. AIFF or WAV sound)
'Totally blown apart'
Tuesday's blast took place in a carriage of the RER train.
Witnesses said the scene was one of panic, of thick black
smoke, the chilling wail of ambulances, and paramedics
frantically carrying away thrashing wounded on stretchers.
"We heard a strong blast," one witness said. "There was a
column of black smoke (and) a strong smell of powder, like
at a shooting range," she said.
The train car was a burned-out hulk of wreckage, its doors
blown off by the force of the blast, and a second car was
damaged. "It was totally blown apart," said a man who lives
above the station.
The explosion occurred on the same line, and two stations
away from the worst of last year's bombings, which killed
eight people at the St. Michel RER station.
Officials said the bomb exploded on one of the first cars of
a long subway commuter train heading toward the southern
Paris suburb of St.-Remy les Chevreuse.
Paris Bureau Chief Peter Humi and Correspondent Jim Bittermann, and Reuters contributed to this report.