A U.N. police vehicle exploded Thursday, killing an international police officer, authorities said. A bomb was suspected to have caused the blast.

The officer, who was not identified, was driving to work when the blast occurred at about 8:20 a.m in Prizren, some 50 miles southwest of province's capital, Pristina (search), said Ken Stica, a U.N. police spokesman.

"I can confirm that an international police officer was killed in an explosion while driving to work," he said.

It was suspected that the explosion was caused by "an improvised explosive device placed under his vehicle," said Fatmir Gjurgjeali, a local police spokesman in the city of Prizren.

An investigation was still under way.

The officer's nationality was not officially disclosed. But, police sources said the officer was from Nigeria.

Some 3,000 international police officers serve in the U.N. force, which was deployed in Kosovo in mid-1999 when the mission started to administer the province.