Sri Lanka has imposed an indefinite curfew in the northeastern city of Trincomalee, following two explosions that killed 18 people, including two policemen.
Local authorities say the policemen were killed when their vehicle struck a land mine. Two other officers were wounded. Authorities are blaming Tamil rebels for the attack.
Hours later, an explosion at a vegetable market killed 16 civilians and wounded an unknown number. Witnesses say the blast also damaged several shops. Rioting erupted after the explosion, with several shops set on fire.
United Nations Secretary-General Kofi Annan and European monitors observing a four-year-old truce between the government and the rebels have expressed concern about the rising violence.
Mr. Annan said he believes it is of utmost importance to find ways to implement the ceasefire agreement and urged both sides to attend peace talks in Geneva next month.
Some information for this report was provided by AFP and AP.