Kabul  - Five Afghan security guards, two civilians, five suspected militants, and two unidentified persons were killed by Afghan and international forces in the latest clashes and explosions in Afghanistan, officials said Saturday.

A bomb hidden in a bicycle went off Saturday in Kandahar city, capital of the province of the same name, killing two civilians including a woman and wounding four more, provincial police chief Matiullah Qateh said.

Five security guards working for a bank were killed in an encounter with unknown gunmen in the northern province of Parwan on Friday night, provincial police chief Khalilullah Zaiyee said.

Four other guards including a policeman were wounded in the clash that took place on the main highway that links Kabul city to the northern region, he said.

It was not immediately known who was behind the attack. Ziayee did not rule out the possibility of criminal gangs being responsible, because the guards were working for a bank.

Separately, Afghan security forces and NATO-led International Security Assistance Force (ISAF) troops conducted an operation in Deh-e-Manakah village of the Mohammed Agha district in the central province of Logar, the alliance said in a statement.

The combined forces killed three insurgents after giving them a chance to surrender, the statement said, adding that the operation followed information provided by local residents.

One rebel was killed and two were wounded when Afghan and ISAF troops targeted them in the Sabari district of the south-eastern province of Khost, an ISAF statement said.

The militants were planting a roadside bomb when they were spotted by an ISAF unmanned aircraft, the statement said. The wounded were detained and bomb-making materials were seized, it said.

An unknown number of suspected Taliban militants were killed Saturday in the Maiwand district of the south's Kandahar province, the US military said in a statement.

coalition forces were fired upon when they reached a targeted compound, the statement said, adding that the troops called in air support when the barricaded militants did not come out of their bunker.

"Due to structural instability of the bunker, the force was unable to verify the number of militants killed but assessed that at least two armed combatants had engaged the force during the clash," the statement said.

In the neighbouring province of Helmand, Afghan and ISAF forces killed a suspected militant and two other persons whose identities were not known on Friday, an ISAF statement said.

The incident happened in Musa Qala district of the province when the individuals were travelling in a vehicle.

About 70,000 international forces deployed from 42 nations are battling the Taliban, who have steadily gained power in the past three years after their ouster in a US-led invasion in late 2001.

Around 25,000 more international combat troops and military advisers were expected to arrive in Afghanistan before the country's presidential election in August.

More than 20,000 of the new forces are to come from the United States and the rest from other ISAF troop-contributing countries. (dpa)