PESHAWAR, Pakistan — Pakistani security officials say suspected militants have launched two separate gun attacks on security convoys in the country's northwest, killing four soldiers and wounding 10 others.

The officials say the ambushes came hours apart Monday in North Waziristan district, a former Taliban stronghold. The attackers then fled toward the border with Afghanistan. The officials spoke on condition of anonymity because they were not authorized to speak to media on the record.

There was no claim of responsibility, but the twin attacks came days after a cross-border attack by dozens of militants killed three soldiers in North Waziristan.

Pakistan and Afghanistan share a rugged 2,400 kilometer (1,500 mile) border. The two nations routinely accuse each other of not taking enough steps to curb the flow of militants within the border region.