European Union nations called Monday for an independent war crimes investigation into the killing of civilians in Sri Lanka.

Foreign ministers from the 27-nation EU said allegations that international humanitarian and human rights laws were violated had to be investigated, but did not say by whom.

"Those accountable must be brought to justice," they said in a statement.

TIMELINE: 25 Years of Civil War in Sri Lanka

British Foreign Secretary David Miliband said there have been "very grave allegations" of war crimes on both sides of the conflict and "they should be properly investigated."

But others said the priority should be on getting humanitarian aid to civilians caught in the crossfire.

The ministers urged authorities to seek reconciliation with the country's minority Tamil population.

"The future of Sri Lanka is dependent on its ability to build an inclusive society for all of its citizens," said Swedish Foreign Minister Carl Bildt. "The sooner that starts the better."

Sri Lanka's government announced Monday it had crushed the 25-year conflict with Tamil Tiger rebels and had killed rebel chief Velupillai Prabhakaran.

The U.N. said 7,000 civilians were killed in heavy fighting between Jan. 20 and May 7. The U.N.'s human rights office said last week there was evidence the rebels had forced civilians to stay in the conflict zone and had shot at those who tried to flee.

EU nations, along with others, have appealed in recent weeks for a cease-fire to safeguard the tens of thousands of civilians trapped in the war zone, but the government refused, denying reports it was shelling the densely populated war zone.

The EU reiterated its condemnation of the Tamil rebels for using civilians as shields and forcibly recruiting them into its militias.

It urged the rebels to "renounce terrorism and violence once and for all."

The EU branded the Tamil Tigers a terrorist organization in 2006, trying cut off funding to the group from EU countries.

The rebels have fought since 1983 for an independent state for the Tamil minority, which suffered decades of marginalization at the hands of governments dominated by the Sinhalese majority. More than 70,000 people have been killed in the fighting.