BEIRUT: At least 24 militants have been killed and 150 wounded in clashes with Syrian troops defending an air base in Raqa province, a monitoring group said on Saturday.

The clashes came as the Is­la­mic State of Iraq and Al Sham (ISIS) group lau­n­ched a new bid to capture the Tabqa base, the government’s last bastion in the northern province, the rest of which is in the hands of militants.

The Syrian Observatory for Human Rights said the attack began overnight when a suicide bomber blew himself up at the entrance to the base, prompting clashes that killed 14 ISIS fighters.

The two sides exchanged rocket, artillery and machinegun fire, and the army deployed air strikes against the attacking militants, the Britain-based group said.

The air raids continued into the morning, with eight strikes against the town of Tabqa that killed 13 people, among them an additional 10 ISIS fighters.

The deaths brought ISIS losses since it began its assault on Tabqa to at least 94, with more than 400 wounded, according to the Observatory.

ISIS has brought in reinforcements from other areas it controls in Syria, as well as neighbouring Iraq, according to the group.

The assault on Tabqa comes after ISIS fighters seized the army’s Brigade 93 and Division 17 posts in Raqa, killing dozens of soldiers, some of whom they beheaded.

The army has airlifted reinforcements to the base and stepped up air strikes against ISIS positions across Raqa, using both precision rockets and barrel bombs.

On Saturday afternoon, Syrian state television broadcast images from Tabqa showing soldiers it said were “ready to repel any new attack”.

It also showed the bodies of what it said were “terrorist mercenaries of the Islamic State”.

“These terrorists have tried to attack the airport several times in recent days but have been repelled by the force and bravery of the army heroes,” it added.

“The Tabqa military airport is secure, the army is defending it and launching attacks against the armed men outside the base,” an officer interviewed at the base told the state broadcaster.

In a related development, the militant Al-Nusra Front posted a video showing kidnapped Lebanese security personnel. The group called on the Hezbollah movement to withdraw its fighters from Syria.

The nine men — apparently eight policemen and a soldier — are among 24 security personnel still in the hands of militants after fighting erupted on the Syrian border earlier this month.

In the video posted on Friday night on Islamist websites, the men are seated in front of a black flag with the logo of Al-Nusra, the Syrian affiliate of Al Qaeda.

Although the men say they are speaking freely, they use the language of Al-Nusra and call on their family members to stage demonstrations and block roads in Lebanon to protest Hezbollah’s involvement in Syria, where the Shia group is fighting alongside the regime to put down a Sunni-dominated uprising.

One of them says the hostages have been warned they will be killed unless their families take action.

Published in Dawn, August 24th, 2014