BAGRAM AIR FIELD, Afghanistan — The Taliban threatened Saturday to launch a fresh offensive across Afghanistan this coming week as President Hamid Karzai said international forces have yet to secure large parts of the country.

The Taliban said the offensive starting Monday will include assassinations of government officials, roadside bombs and suicide attacks against foreigners and those who support them.

"All foreign invading forces will ultimately face defeat," the Taliban said in a statement sent to reporters from an e-mail address used by the militants.

Defense Minister Gen. Abdul Rahim Wardak quickly dismissed the threat as insurgent propaganda.

A crucial test of the nine-year war is coming this summer, when a U.S.-led military operation tries to clear the Taliban from the key southern city of Kandahar, the group's spiritual heartland.

Insurgents have ramped up attacks there recently. On Saturday, the Taliban claimed responsibility for the death of a government official in Arghandab in Kandahar province.