Colombo, Sri Lanka - A Sri Lankan bishop has written to the Vatican accusing the country's navy of a grenade attack on a church in which a woman died and 40 others were hurt.
The church in Mannar was "desecrated", Bishop Rajappu Joseph said. Sri Lankan authorities deny involvement.
Meanwhile, Tamil rebels have demanded European Union truce monitors leave Sri Lanka after the EU banned the group.
The rebels also raised the spectre of suicide bombings, threatening to use "all resources" in the event of war.
'Innocent blood'
Reverend Rajappu Joseph Navy accused navy personnel of forcing their way into the Our Lady of Victory Church in Mannar last Friday.
Tamil Tiger political leader SP Thamilselvan
We definitely will make use of all the weapons in our arsenal
The church "had been desecrated by innocent blood being shed by unjust aggressors, the Sri Lanka Navy", he told the Vatican.
The government denies the allegations, but eyewitnesses described how the military attacked the church. An international aid worker also confirmed it.
Some 200 people had been sheltering in the church when a grenade was thrown in.
The government says the church was caught in the middle of an exchange of fire after a major navy-rebel clash at sea.
On Wednesday, Norwegian ambassador Hans Brattskar met Tamil Tiger leaders in the rebel-controlled northern town of Kilinochchi.
A Norway embassy official said that the rebels had said monitors from Sweden, Finland and Denmark would have to leave the Sri Lankan Monitoring Mission which oversees a tattered four-year-old truce.
"They don't accept SLMM members from countries which have proscribed them as a terrorist organisation," Erik Ivo Nurnberg of the Norwegian embassy is quoted as saying by Reuters.
'Ready for war'
The truce has been described by Tamil Tiger political leader SP Thamilselvan as "just a piece of paper that has no meaning at all".
In an interview with the Associated Press, Mr Thamilselvan also said they would use all means necessary in the event of all-out war.
"We definitely will make use of all the weapons in our arsenal - not only weapons but manpower," he said.
Asked if this meant suicide bombings, he said: "In facing war... of course we will use all our resources."
Violence in Sri Lanka has claimed hundreds of lives since late last year.
The rebels have been fighting for an independent Tamil homeland for over two decades. More than 60,000 people have died.