Afghan police say an explosion killed eight people and wounded 16 others in Helmand province, where Afghan and NATO forces are conducting a major offensive against Taliban militants.

Police say the bomb went off in front of a government building Tuesday in Lashkar Gah, the capital of the southern province.

In the nearby town of Marjah, U.S. military officials are reporting slow but steady progress in the operation targeting Taliban fighters.

The security gains NATO is reporting have been overshadowed by civilian deaths caused by a NATO air strike in a nearby province.

On Tuesday, U.S. General Stanley McChrystal apologized directly to the Afghan people for the strike in Uruzgan province, which the Afghan government says killed 27 civilians.

In a video posted on the NATO Web site and translated into the local languages Dari and Pashto, McChrystal pledged to regain the trust of the Afghan people.

McChrystal apologized directly to President Hamid Karzai Sunday, shortly after the incident in Uruzgan province.

In Washington Monday, NATO Secretary-General Anders Fogh Rasmussen also expressed regret over the civilian casualties.

Rasmussen said he believes there is new momentum in Afghanistan, and he expressed confidence that allied forces will be able to start transferring security responsibilities to Afghan units later this year.

Some information for this report was provided by AP, AFP and Reuters