The United States Tuesday urged Sri Lanka's Tamil rebel movement to end violence and engage in peace talks with the Colombo government. At least 40 government military personnel have been killed this month in an upsurge of violence.

The United States has joined fellow sponsors of Sri Lankan peace efforts in urging Tamil rebels to end attacks and return to peace talks.

The U.S. appeal followed what is being described as the worst month of violence since the Colombo government and the Tamil separatist movement, the Liberation Tigers of Tamil Eelam or LTTE, signed a cease-fire in February of 2002.

The attacks have killed about 40 Sri Lankan military personnel including at least 10 who died in landmine blast Tuesday.

The violence has raised fears the island could return to civil war, and spurred international calls for peace talks, including a direct appeal to LTTE leaders last Saturday by diplomats from Japan, Norway, Britain and the European Union.

The diplomats, at the meeting in the northern rebel stronghold of Kilinochi, called for an immediate end to rebel violence and for the LTTE to engage positively with the government in peace talks.

They said a failure to heed the call would have serious consequences, while also calling on the Colombo government to end activities by paramilitary groups.

State Department Deputy Spokesman Adam Ereli issued a statement on the Sri Lankan situation, saying U.S. officials did not attend the Kilinochi meeting but support the diplomats' message "in the strongest possible terms".

"We weren't part of that meeting but we definitely support that call," he said. "And we are concerned by an erosion of the four-year-old ceasefire, as evidenced by the recent up-tick in violence."

The statement said the United States recognizes that lasting peace in Sri Lanka can only be achieved by Sri Lankans themselves. It urged both sides to embrace peace and work together to build a better future for the country.

The United States, the European Union, Japan and Norway co-chaired an international donors conference in Tokyo in June 2003 that raised more than four billion dollars in reconstruction aid to support the peace process.

The co-chairs have held periodic review meetings since then, the most recent one held in Brussels December 19.

There had been broad hopes in the international community that cooperation between the Sri Lankan parties in delivering relief aid from last year's tsunami disaster would help build confidence between the sides.

But the hopes have faded amid disagreements over aid-sharing, and the election in November of a new Sri Lankan president who rejects the rebels' key demand for an independent homeland.

Spokesman Ereli said U.S. diplomats have discussed the latest violence with officials of the government of President Mahinda Rajapakse.

Mr. Rajapakse went to New Delhi Tuesday for his first state visit since his election, and is expected to urge greater Indian participation in Sri Lankan peace efforts, though India has been reluctant to assume such a role.