A NATO bomb mistakenly hit a house 1 1/2 miles off target Tuesday, killing two civilians and wounding 10 even as Afghanistan''s president was saying that terrorism cannot be defeated if innocents are killed in coalition operations.

In a separate incident in eastern Afghanistan, a roadside bomb killed an Afghan contract worker and three soldiers in the U.S.-led coalition, the coalition said.

NATO said the bomb that went off target was aimed at a spot used by insurgents to fire rockets in eastern Khost province but the weapon malfunctioned and hit a civilian house.

"An immediate investigation into the cause of the incident has been launched and further details will be forthcoming once established," a NATO statement said.

Because of Afghanistan''s mountainous terrain and few roads, foreign troops rely heavily on air power to combat Taliban and al-Qaida fighters. But airstrikes have been blamed for a series of civilian deaths, and President Hamid Karzai is pushing for a review of the use of U.S. and NATO air power.

He raised that theme again Tuesday after attending the inauguration of Pakistan''s new president, Asif Ali Zardari.

"The war against terrorism will only be won if we have the people with us. There is no other way. In order for us to have the people with us, we must avoid civilian casualties," Karzai said.