A rocket grenade has exploded near Zaragoza airport in Spain, causing no injuries. The blast followed a warning call in the name of ETA to a Basque newspaper. The airport in Zaragoza, 250 kilometres northeast of Madrid, was evacuated before the blast, and one Ryan air flight was diverted to a nearby military base. Police found two rocket launchers in undergrowth 100 metres outside the airport perimeter.

One was empty, presumably after firing its charge, and the second contained a grenade which was defused by bomb experts, according to the Interior Ministry.

Maria Teresa Fernandez de la Vega, the number two in Spain's Socialist government, said: "We condemn strongly what happened and we repeat once again that the only response to terrorism is the utmost vigilance, maximum efficiency for the security forces, and maximum international cooperation and unity between political forces to put an end to terrorists."

The attack is the latest of several linked to ETA since Madrid said last month it was open to negotiations with the Basque separatist group if it laid down its arms and renounced violence. None of the attacks, including a car bomb in Madrid, have caused serious injury.

Socialist Prime Minister Jose Luis Rodriguez Zapatero has been forced to defend his offer since it won endorsement from parliament last month. Hundreds of thousands of Spaniards demonstrated against it last Saturday, calling it a betrayal of the 850 victims ETA has claimed since 1968.

PHOTO CAPTION

A civil guard armoured vehicle passes a radio press van near the spot of a granade attack at the airport in Zaragoza, Spain Friday June 10, 2005. (AP)