New U.S. offensive in Kandahar has already started, the top U.S. and NATO commander in Afghanistan said on Wednesday, offering few details.

General Stanley McChrystal told reporters that the US-led offensive on the Taliban's spiritual heartland had started with initial military and political efforts, including operations designed to secure key roads and districts surrounding the southern city.

That has raised questions about how to identify the new campaign in Kandahar and its surroundings, where NATO already has thousands of forces, Reuters said.

His comments came after what Taliban said response attack to U.S.-led offensive. On Sunday, a major bombing attack killed 35 people in Kandahar.

"Kandahar is already being shaped," McChrystal said, briefing reporters in Washington via teleconference, adding that efforts will "ramp up" in the coming weeks and months.

McChrystal said there would also be more partnering with Afghan police inside Kandahar city and boosting troop levels in the surrounding areas.

"If you control the environs around Kandahar, you go a long way to controlling Kandahar," he said.

Political situation

Referring to "complex" political conditions in Kandahar, he said coalition forces would be working "to shape the political relationships in and around Kandahar," but offered no details.

McChrystal has not given a timeline for the operation but told reporters last week in Kabul that troops would be at full force for Kandahar operations by the early summer.

"We see indications that they are trying to figure out what way ahead that they should plot," he said.

Kandahar served as the spiritual seat of power for reclusive Taliban leader Mullah Mohammad Omar before their administration was ousted by U.S.-backed invasion in 2001.

Agencies