KABUL: A bomb exploded near a military vehicle in eastern Afghanistan on Tuesday, killing three international troops and wounding one, officials said.

The explosion took place outside the capital of Kapisa province, said Lt. Commander Christopher Hall, a spokesman for the international military coalition. He did not provide further details or the troops' nationalities.

Provincial officials said a suicide bomber rammed into the vehicle in a Toyota Corolla. One Afghan civilian was also killed in the blast, said Abdul Halim Ayar, a spokesman for Kapisa's governor.

Roadside and suicide bombings have spiked in recent months. Such attacks were up 25 percent the first four months of 2009 compared with the same period last year, U.S. military officials have said. They have predicted that bomb attacks will rise 50 percent this year to 5,700 — up from 3,800 last year.

Such attacks killed 172 coalition forces last year — and far more Afghan civilians — according to military figures.

Meanwhile, U.S. forces said they killed eight Taliban fighters in a clash in the southern province of Uruzgan on Monday. The coalition said two of its troops and three Afghan policemen were wounded during the clash.

They were undergoing medical treatment and were in stable condition. The troops were on patrol when Taliban fighters attacked them with small arms fire and heavy machine-guns.