Police fired tear gas Saturday at a crowd of opposition supporters who threw stones at buses allegedly transporting supporters of the ruling coaliton, witnesses and opposition officials said.

Police, however, denied tear gas was used but acknowledged dispersing opposition workers who stopped two buses in the northeastern state of Terennganu. The conflicting claims could not be immediately reconciled. Police said 19 people were arrested.

The trouble started when the opposition Pan-Malaysian Islamic Party workers stopped two buses, which they suspected were carrying supporters of the ruling National Front coalition pretending to be voters from the district, said PAS official Umar Abdullah.

"There were some skirmishes and police fired tear gas," he said. The claim was corroborated by witnesses who spoke on condition of anonymity for fear of getting into trouble with authorities.