BANGKOK, THAILAND (AFP) - Thailand's premier warned Friday of possible further bomb attacks in Bangkok after a grenade blast left one man seriously hurt, days after a deadly explosion at a bus stop.

The grenade, which was in a plastic bag, exploded before dawn on a street in the capital, leaving a rubbish scavenger in critical condition with shrapnel in his head, police and hospital officials said.

"It's likely that the bomb was aimed at inciting unrest," Prime Minister Abhisit Vejjajiva told reporters.

"The overall assessment and evaluation of the situation is that more bomb attacks are likely at this time," he said.

The blast came less than a week after a small bomb exploded at a Bangkok bus stop, killing one person and injuring 10 in an attack that rekindled tensions in the capital two months after the end of bloody street protests.

About 90 people died and some 1,900 were injured in street clashes between armed troops and demonstrators during two months of mass rallies by the anti-government "Red Shirts" that ended with a bloody army crackdown in May.