After four years, Canadian forces have transferred command of Kandahar city to the U.S., as thousands more American troops prepare to mount an offensive against the Taliban.

Under a reworked system of command, Canada will command a unit the size of a brigade to the south and west of the city, in the districts of Dand, Daman and Panjwaii. The unit will report to NATO's southern command.

Panjwaii is one of the areas the Taliban originated in, and has been a troublesome district for Canadian forces trying to quell the insurgency.

Brig.-Gen. Jonathan Vance, the commander of Task Force Kandahar, told The Canadian Press recently that the new command structure "makes a lot of sense."

"We're able to concentrate force, concentrate focus and so we can deal in detail with the sort of tactical challenge in making sure that districts and villages within those districts start to rebound."

The hand-over took place two weeks after the Americans took command from Canada over the Zhari and Arghandab districts in Kandahar province. It also occurred without much of a ceremonial display.

Canada has more than 2,700 troops in Afghanistan, mainly in Kandahar province. They assumed command of Kandahar province in 2005. Since entering the war in 2002, 150 Canadian soldiers have died in that country.

Under the reorganized command, Canadian forces are expected to be spread less thin, CTV's South Asia Bureau Chief Janis Mackey Frayer reported from Kandahar.

"It was not really a surprise that this transition was going to happen, since U.S. President Barack Obama announced 30,000 U.S. troops were coming to this country," she told CTV News Channel. "Still, this is a significant shift in the Canadian dynamic."

Lt.-Col. Craig Dalton, the chief of staff for Task Force Kandahar, said the move is part of a "gradual transition" as additional U.S. troops arrive in the war-torn country. He added that American troops will assume full command of Kandahar city within a few weeks.

Washington is in the midst of a troop "surge" that will see the number of NATO soldiers in Kandahar province reach 21,000 by summer's end -- three times more than were stationed there a year earlier.

By the end of August, 140,000 NATO troops will be stationed across Afghanistan, most from the U.S.

In Kandahar province, Mackay Frayer said the conflict between the Taliban and NATO troops will likely become bloodier as more troops continue to arrive.

"Soldiers tell us that IEDs really are everywhere, and the insurgency seems to be more clever and more cunning in where they're able to plant them," she said. "So there is the expectation that casualties will mount."

"It's very contested ground. You have two very determined forces who want the same thing."

With files from The Canadian Press