KANDAHAR — Firefights broke out between foreign forces occupying Afghanistan and local police in two parts of the country on Tuesday night, with four Afghan officers killed in one of the incidents, officials said Wednesday.

According to The Associated Press, in southern Kandahar province, Afghan police and NATO troops clashed in Arghandab district -- a farming community just outside of Kandahar city, said Shah Mohammad, the top official for the district. He said four Afghan police officers were killed and four wounded.

It was not clear what started the firefight and Mohammad said that investigators had been dispatched to the site to investigate the cause.

“Right now we only have this very sad news from there,” he said.

A NATO spokesman confirmed that there was “an incident” in Arghandab, but did not provide further details. Capt. Justin Brocckhoff said more details would become available after an investigation.

In the eastern province of Ghazni, meanwhile, NATO forces fought briefly with Afghan police manning a checkpoint in Ghazni city before the two groups realized the mistake.

The NATO troops approached the checkpoint while on a nighttime patrol through the area, provincial Police Chief Gen. Zarawar Zahid said. The Afghan police saw armed men and asked them to stop and started firing when the NATO troops did not, Zahid said.

The exchange of gunfire lasted about 15 minutes and no NATO or Afghan forces were killed, Brockhoff said. He said an investigation had also been launched into that incident.

Meanwhile, a police inspector was shot dead in Kandahar city Tuesday night by unknown gunmen, said Deputy Police Chief Shershah Yousafzai. Yousafzai said they suspected he was killed by militants. The Taliban has repeatedly targeted Afghan forces and police.

NATO keeps up pressure on Taliban 

In spite of losing 30 U.S. soldiers in an air crash on Saturday, NATO troops and Afghan police have been mounting pressure on Taliban since the weekend, Xinhua reported.

In the latest operations against Taliban fighters, Afghan police captured a Taliban commander in country's Baghlan province 160 km north of capital city Kabul on Tuesday, provincial police chief, Abdul Rahman Rahimi said.

"After a siege and search operation, police captured a Taliban commander Mullah Jamaluddin in Burka district Tuesday morning," Rahimi told reporters in provincial capital Pul-e-Khumri.

The detained Jamaluddin had served as Taliban commander in Burka and adjoining areas and was responsible for organizing suicide attacks, Improvised Explosive Device (IED) blasts and targeting security forces, the official in Baghlan added.

At least 27 Taliban fighters have been killed by police during operations backed by Afghan army and ISAF, since Saturday, Afghan Interior Ministry confirmed in separate statements released here.