The European Union, which earlier in the week banned Sri Lanka's Tamil Tiger rebels, said Wednesday it was willing to take "further measures" to push the warring parties back to the negotiating table.

A declaration by the EU presidency, currently held by Austria, said the ban on Tamil Tiger rebels should not have come as a surprise, but the Sri Lankan government too must curb violence in areas under its control.

"The EU will keep the situation in Sri Lanka under active review, taking account of the activities of all parties to the conflict," a seven-point declaration said.

"It will remain ready to adopt further measures as and when they may be warranted by changing circumstances."

It did not spell out the possible measures, but noted that the escalation of violence in the island, where more than 600 people were killed since December despite a 2002 truce, was not the fault of the the Tamil Tigers alone.

"The upsurge in violence is not caused by the LTTE (Liberation Tigers of Tamil Eelam) alone," said the declaration, a copy of which was sent here by the EU delegation in Colombo.

"The EU strongly urges the Sri Lankan authorities to curb violence in government-controlled areas. The EU notes with concern the growing number of reports of extrajudicial killings."

The Tigers have accused troops of collaborating with a breakaway rebel faction to attack it, a charge denied by the military. Scandinavian truce monitors, however, said evidence on the ground suggested collusion.

"The EU stands by all of the findings in the reports of the SLMM (Sri Lanka Monitoring Mission)," the declaration said.

"The EU urges the government of Sri Lanka to act effectively on the commitment of President Mahinda Rajapakse to put a stop to the culture of impunity and to clamp down on all acts of violence in areas controlled by the government."

The EU council of ministers on Monday added the LTTE to a list of terrorist organisations clearing the way for a EU-wide crackdown against fund raising and other activities of the rebels.