A suicide bomber targeted an Afghan army convoy in southern Afghanistan Sunday, killing 10 civilians as two other people were killed in an explosion at the New Year's celebration in eastern region, officials said.

The bomber, who was driving a motorbike loaded with explosives, targeted the army convoy in the main market of Gerishk district in southern province of Helmand Sunday afternoon, Daoud Ahmadi, spokesman for the provincial governor said.

'Ten people were killed and seven others were injured. They are all civilians,' Ahmadi told DPA. He did not know whether there were any casualties among the soldiers.

The attack took place on a bridge in the district, destroying the bridge and plunging a number of people down into the river, he said, adding 'The death toll could rise'.

Meanwhile, two other people were killed and four injured Sunday when a bomb was detonated near a large crowd in Koh Baba area of south-eastern province of Khost, Mohammad Yaqoub, the provincial police chief said.

It was not known if the explosion was triggered by a roadside bomb or explosive hidden inside a vehicle, he said. Several vehicles parked near a shrine, where the people had gathered to mark the new year day, were damaged.

At least three explosions also rocked eastern city of Jalalabad, the capital for Nangarhar, Saturday night, but there were no casualties, Abdul Ghafour, a police spokesman in the province said.

The blasts occurred near a compound, where the provincial governor and the local residents were celebrating the new year eve.

Afghan security forces have boosted their presence in major cities, including Kabul, in the past three days as authorities had warned of more Taliban attack during the new year festivities.