A series of bomb blasts in Afghanistan on Wednesday killed five police and guards in the latest attacks linked to a Taliban insurgency expected to intensify in the coming months.
In one incident a parked motorbike packed with explosives detonated near a van of a US-based security firm accompanying a NATO convoy through the volatile southern province of Kandahar, killing two Afghan guards, the company said.
Six other men in the US Protection and Investigation (USPI) vehicle were wounded in the attack and three of them were critical and in a coma, said the head of security for the convoy, Abdul Khaliq.
The van had been escorting a convoy that was supplying logistics to NATO-led International Security Assistance Force (ISAF) troops when it was hit in the volatile Maiwand district of Kandahar, the Taliban's birthplace.
The district governor, Haji Saifullah, said it was a remote-controlled bomb.
The attack was around 100 metres far from the district headquarters on a major highway that links Kandahar city with the western capital of Herat and Kabul.
The officials did not say who might have been behind the attack but the area has seen some of the worst fighting in a Taliban-led insurgency launched after the extremist movement was driven from government in late 2001.
Another blast occurred while police were defusing a remote-controlled bomb in the Shindand district of Herat province.
It killed three of Zir Koh district's top police officers, including the criminal investigation and police operations directors, said the police commander for western Afghanistan, General Akramudin.
A third remote-controlled bomb hit a patrolling police vehicle in the southwestern province of Nimroz, the provincial police chief said.
"Their vehicle was targeted by a remote-controlled bomb. Three police were wounded and their vehicle was destroyed," Mohammad Daud Askarzada said.
Insurgency-linked violence killed more than 4,000 people last year in Afghanistan, a fourfold increase on the year before, according to figures from various officials. Most of the dead were rebel fighters.
The Taliban has warned it will unleash a storm of attacks this year. ISAF has downplayed the threat but US military officers have said the violence will likely pick up after spring in March.
Foreign forces in Afghanistan, which together have around 45,000 troops here, are positioning themselves for the challenge with requests for extra troops and equipment.
The German cabinet voted on Wednesday to send up to eight Tornado jets to Afghanistan for use in surveillance operations and up to 500 soldiers to man them, officials said.
The decision still needs to be approved by parliament.