Tens of thousands of rival demonstrators flocked to northern Spain today for mass demonstrations over proposals for an independent Basque state and the government's handling of ETA separatist rebels.
It was the first time the two sides in the bitter dispute over independence for Spain's Basques had faced off after weeks of protests by the opposition Popular Party and ETA victims over government concessions to end a separatist's hunger strike.
Regional elections are due in May and a national vote in 2008, and the demonstrations were viewed as opposition moves to score points against the government over ETA violence, judged the country's greatest problem in opinion polls.
Political leaders asked for calm as busloads of Popular Party supporters drove to Pamplona for a march against plans to include its Navarra region in ETA peace talks. ETA's political ally Batasuna proposed in February that Navarra and the Basque country form an independent Basque state.
The Popular Party alleges the socialist government is in talks with Batasuna to include Navarra in a future peace process to end ETA's fight for an independent Basque state.
The opposition opposes talks with ETA until the group surrenders its arms, having killed nearly 850 people in the last four decades to back its demands for independence.
The Spanish government called off a previous ETA peace process in January after rebels killed two people in a car bombing at Madrid's Barajas international airport.
Trade unionists backing Basque independence plan to march within 100 metres of the opposition demonstration.
Hundreds of thousands of Popular Party supporters demonstrated in Madrid last Saturday to protest against the government's decision to grant house arrest to ETA convicted killer Inaki de Juana Chaos after he fell dangerously ill while on hunger strike.