Spain sent in the army to guard its railways yesterday after finding a bomb on a high- speed track that may contain the same explosives used in last month's Madrid train bombings.
Interior Minister Angel Acebes said police would check the 350 km/h Madrid-Seville line on which the bomb was found kilometre by kilometre and would then use helicopters and army vehicles to guard key tracks.
The 12 kg of dynamite packed in a bag, was found near the central city of Toledo and defused safely.
But the scare disrupted travel as millions of Spaniards prepared to leave cities for the Easter week holidays and came on the day a new session of parliament opened after last month's elections.
The possibility that the explosives, although not uncommon, could be of the same type used in the pre-election bombings of four Madrid commuter trains which killed 191 people on March 11 will raise fears that the al Qaeda-linked group believed to have masterminded the attacks could still be operational.
"The specialists say it could be the same as was used on March 11," Acebes told a news conference after talks with Defence Minister Federico Trillo.
The discovery also highlights the vulnerability of Europe's high-speed rail lines which cover thousands of kilometres and would be impossible to secure fully. A successful attack on a speeding and packed express could exact a heavy toll.
Investigators believe the bombers wanted to blow up the track and derail a train, but either the bomb was not connected properly or the attempt was aborted because they were interrupted, Interior Ministry sources said.
Acebes said security forces believed the bomb was planted yesterday morning as the bag was dry and the cables new.
The operation to patrol the rail line would involve the armed forces, police and rail guards, backed by 45 helicopters, police dog units and army all-terrain vehicles, including armoured vehicles, he said.
A Reuters reporter at the scene said the bomb had been in a hole close to where the road crosses the track.
The AVE high-speed link whisks passengers from Madrid to Seville in a little over two hours and is one of the jewels of the Spanish rail network. Services on the line were halted while all the track was checked.
The Madrid attacks were the first in the West linked to Osama bin Laden's al Qaeda network since the September 11, 2001, strikes on New York and Washington.
Yesterday's bomb was found as members of parliament elected in Spain's March 14 election took their seats in Madrid. The Socialists ousted the ruling Popular Party in an election upset three days after the March 11 bombings.