Kabul  - Two blasts in Afghanistan killed four civilians including a child, while at least 15 Taliban militants were killed in separate operations elsewhere in the country, officials said on Saturday.

The blast was triggered by explosives attached to a parked bicycle in the western part of Kandahar city, the provincial capital of the same name, on Saturday morning as a police vehicle was passing by, said Mohammad Iqbal, a police official at the scene of the incident.

The explosive that was detonated by a remote-controlled device killed a child and wounded two police officers and two civilians, he said.

In a similar incident in south-eastern Paktia province on Saturday, three civilians were killed when their vehicle was blown up by a roadside mine, provincial spokesman Ghamai Khan Mohammadi said.

He said that the bomb was newly planted on the road, which is often used by Afghan and international forces in the province.

Taliban militants, whose government was ousted in a US-led invasion in late 2001, have stepped up their attacks, mainly by roadside and suicide attacks, both tactics widely believed to have been copied from Iraqi insurgents.

In another incident, 15 Taliban militants were killed in Bala Boluk district of western Farah province in an operation by Afghan forces backed by US-led coalition air-support, General Abass, army commander in the western region, told Deutsche Presse-Agentur dpa.

Three other militants, including a Taliban commander, were arrested by army forces in the operation, dubbed Shamshir Bazaar (Bazaar of Swords), which started on Friday and was still ongoing, Abass, who goes by a single name, said.

"A Taliban hideout was bombed and destroyed by coalition aircraft and (this) killed 15 anti-government elements," the army general said, adding that the forces also rescued two kidnapped government employees from Taliban custody.

Meanwhile, the US military said that its forces had killed "several extremists" and arrested four in an operation aimed to disrupt militant activities in the south-eastern province of Khost on Friday.

"During their search, the joint force identified two armed militants manoeuvring against their force. They responded with small arms fire and airstrikes, killing both militants," the military said in a statement.

In a separate operation, also on Friday, coalition forces detained eight other Taliban militants in eastern Nangahar province, the statement said.

The operation had targeted a Taliban militant known to have facilitated roadside and rocket attacks against the Afghan and coalition forces in the region, the military said. (dpa)