Suspected militants attacked a second military convoy Wednesday in northwestern Pakistan, detonating a remote-control bomb and opening fire to kill 16 soldiers and wound 14 others, the army spokesman said.

The assault, and an earlier one that wounded as many as seven people, occurred in North Waziristan, where militants have stepped up attacks in recent days, said spokesman Maj. Gen. Waheed Arshad.

The ambushers first detonated a roadside bomb, then fired AK-47 assault rifles from nearby bushes at the convoy, about 25 miles west of North Waziristan's main town of Miran Shah, said a senior military official.

The surviving troops returned fire as two helicopter gunships hovered overhead, said the official who spoke on condition of anonymity because he was not authorized to speak with the press.

Earlier, an explosion hit another convey along the road that links Miran Shah with the nearby city of Bannu.

Arshad said one soldier and five or six civilians were wounded, but he had no further details on the bombing.

Troops opened fire after the bombing near the convoy, wounding a 15-year-old boy, an intelligence official said.

The boy, who was hit in the leg and right hand, told an Associated Press reporter from his hospital bed in Miran Shah that he was bathing in a stream near the road when troops opened fire.

Militants have stepped up attacks in North Waziristan in recent days. A suicide bomber Tuesday struck a security check post in the same area, killing three soldiers.

Also Wednesday, five rockets were fired at Miran Shah, one striking the runway at a military airstrip while the others landed near a bazaar and a residential area for civil servants. There were no casualties, said the official who demanded anonymity because of the sensitive nature of his job.

Separately, an explosion ripped through the main entrance to the home of a pro-government tribal elder but caused no casualties. The official blamed militants for the explosion.

Scores of tribesmen and tribal elders have been killed in suspected militant attacks in recent years in the region after they were accused of collaboration with authorities or spying for the United States.

Security officials have said that Afghan, Arab and Central Asian militants — allegedly with links to Al Qaeda and the Taliban — operate in the area, along with local Islamic extremists.