At least 16 suspected militants and one soldier were killed in clashes in northwestern Pakistan's Swat Valley, the military said Sunday as it escalated its offensive against insurgents in the one-time tourist haven.

Swat lies outside the tribal regions along the Afghan border where the Taliban and Al Qaeda have traditionally had their strongholds. Residents say militants now control most of the valley, despite an army operation that began more than a year ago.

The military recently vowed to reinvigorate its efforts in Swat, where Taliban fighters have set up their own courts, destroyed scores of girls' schools and reportedly driven out hundreds of thousands of residents.

The latest clashes broke out in several parts of the valley over 24 hours, according to a military statement that detailed the casualties. It said troops "consolidated their hold" over Charbagh, an area considered a militant stronghold.

Separately, militants fatally shot a police constable they had abducted in Rahimabad, a city in the Swat Valley, the statement said.

Swat's police forces have been decimated by desertions and militant killings over the past 18 months, underscoring the power vacuum in a region that — unlike the tribal areas — is supposed to be under full government control.

Swat is less than 100 miles (160 kilometers) from Pakistan's capital, Islamabad, and there are fears that the militancy could spread beyond the valley to other parts of the country.

Meanwhile, a police official said a grenade attack killed one person and wounded five others in southwestern Pakistan.

The attackers — two motorcyclists — lobbed a hand grenade at a police patrol in Baluchistan province Saturday night, but hit bystanders instead, Ghulam Ali Lashari said.

No one claimed responsibility for the attack in Khuzdar district, about 185 miles south of the provincial capital, Quetta. However, Baluch nationalist groups often attack security forces.

The groups are involved in a low-level insurgency seeking greater provincial autonomy and a larger share of revenue from the region's natural resources.