A Canadian soldier stands on alert at a roadside checkpoint in Arghandab district on Tuesday. (Allauddin Khan/Associated Press)

A Canadian platoon in Kandahar came under fire late Tuesday, the same day officials said the Canadian military is among the feared targets of a possible Taliban attack on the city.

No Canadian soldiers were injured as half the platoon, out on evening patrol, exchanged gunfire with Taliban militants. The other half of the platoon's vehicles crossed a culvert and found a 27-kilogram bomb that had already been disarmed by Afghan police.

Earlier Tuesday, Ahmad Wali Karzai, president of the Kandahar provincial council, told CBC News that intelligence suggested Canada's provincial reconstruction team could come under attack, after hundreds of Taliban fighters reportedly took over several villages near Kandahar Monday. Other officials have suggested such reports are exaggerated.

Karzai, the brother of Afghan President Hamid Karzai, said police headquarters and his own home are also targets.

The Canadian platoon was patrolling potential target zones Tuesday night when they came under fire, including the governor's residence, a power station close to where the bomb was found and Sarposa prison, where a sophisticated attack by insurgents freed hundreds of insurgent fighters last week.

Both Canadian and NATO officials have cast some doubt on the possibility of a full-scale Taliban attack on Kandahar, saying Taliban militants have entered some villages but that a major confrontation was not expected.

NATO spokesman Mark Laity issued a statement Tuesday that said patrols through the region had not found evidence the Taliban is in control of the areas around Kandahar, despite reports that some villages in the area had been captured.

The Pentagon has also dismissed predictions of a major attack.

"In talking to our folks, they do not have any imminent concern that Kandahar is about to fall to the Taliban," said U.S. Defence Department press secretary Geoff Morrell.

Officials have admitted, however, that Taliban fighters appeared to be mobilizing in the Arghandab region, about 15 kilometres northwest of Kandahar. Local officials and residents reported militants had been bombing bridges and planting landmines in the villages around the region.

Coalition troops on Tuesday were increasing their presence in Arghandab, according to Lt.-Col. Dave Corbould, commanding officer of the battle group of 2nd Battalion, Princess Patricia's Canadian Light Infantry.

"It is clear that Kandahar City remains firmly under the control of the Afghan government and its people," he said.

"Indeed, having just returned from the Arghandab district centre, I can tell you that there were no obvious signs of insurgent activity," Corbould said.

"While this does not mean the Taliban are not there, they just do not appear to have the foothold that they have apparently claimed."

Taliban may have inflated numbers

It was unclear how many Taliban fighters had moved into the region, as the Taliban has been known to inflate its numbers. Reporting from Kandahar, the CBC's Paul Hunter said estimates suggest there could be 650 militant fighters surrounding Kandahar city.

"We've occupied most of the area, and it's a good place for fighting," Mullah Ahmedullah, a Taliban commander, told the Associated Press. "Now we are waiting for the NATO and Afghan forces."

The Canadian Forces' 2,500 soldiers in Afghanistan were already primarily based in Kandahar.

The Afghan army, meanwhile, has flown planeloads of 700 soldiers from the capital of Kabul to Kandahar for reinforcement, NATO has confirmed, while other NATO countries already serving in Afghanistan's south have also redeployed their troops specifically to the Kandahar area.

NATO has airdropped leaflets into various neighbourhoods in the area, advising citizens that it is prepared to deal with any threats. The leaflets warn residents to stay indoors and keep their families safe.

Afghan police and troops have enforced a strict 10 p.m. curfew in the city.

'We are deeply worried': fleeing resident

Residents, fearful of the potential attack, fled Arghandab in droves Monday night and Tuesday.

"Last night, people were afraid, and families on tractors, trucks and taxis fled the area," said Sardar Mohammad, a police officer manning a checkpoint on the east side of the Arghandab River.

He estimated that more than 700 families — 4,000 people in all — had fled the Arghandab region, a lush farming area filled with grape and pomegranate groves. He said the Taliban has seized control of nine or 10 villages in the region, which was once a Taliban stronghold.

Residents said they had no choice but to go.

"They told us to leave the area within 24 hours, because they want to fight foreign and Afghan troops," said Haji Ibrahim Khan, relaying what Taliban fighters told him. "But within a week we should be harvesting, and we were expecting a good one.

"Now with this fighting, we are deeply worried. The grapes are the only source of income we have."

Hunter said the Taliban has gained strength after its sophisticated attack Friday on Sarposa prison, in which militants managed to set 400 Taliban detainees free.

"The talk around Kandahar today is they are reinvigorated and emboldened, and morale amongst the Taliban is strong because of the [symbolism] of what happened Friday," Hunter said.

With files from the Associated Press