COLOMBO, Sri Lanka (AP) _ Explosions rocked two buses in Sri Lanka on Tuesday night, wounding at least 28 people, police said.

The first blast occurred at Watalla bus station, seven miles north of the capital, Colombo, and injured 15 people, police said.

A short while later, another explosion wrecked a bus at Colombo's main bus station, wounding at least 13 people, police said.

There was no immediate claim of responsibility for the explosions. But police said they suspect Tamil Tiger rebels were involved.

The guerrillas have been fighting for a separate homeland for the minority Tamils in the island nation's north and east since 1983. They often carry out attacks in the Sri Lankan capital to attract attention to their cause.