Intensifying attacks against security forces following the bloody crackdown on the Lal Masjid in Islamabad, pro-Taliban militants on Wednesday killed at least 16 soldiers and injured 21 people in two separate strikes in Pakistan's restive tribal region bordering Afghanistan.

Militants fired at a military convoy at Madakhel area in North Waziristan tribal agency killing 16 soldiers, the army said.

Around 14 soldiers were also injured in the attack near the Afghan border, defence spokesman Major General Waheed Arshad said.

Defence officials said the exchange of fire left some militants dead too.

In another incident, seven persons, including a soldier, were injured in a roadside blast near a convoy of security forces close to Miranshah, the headquarters of North Waziristan.

Arshad said the bomb was exploded through a remote control when several army and private vehicles were passing by the area.

Local TV channels reported that the security forces fired at the direction from where the attack was carried out. A private car also came under attack, which later fell down from a bridge.

Since the July 11 military operation against the pro-Taliban Lal Masjid in central Islamabad, militants have been targeting the convoys of security forces with either suicide bombings or through direct attacks as the Pakistan Army stepped deployment of troops in the troubled tribal belt to establish its writ.