Activists say insurgents have captured strategic hills and a power station in northwestern Syria, bringing them closer to strongholds of President Bashar Assad.

The Britain-based Syrian Observatory for Human Rights and the Aleppo Media Center said militants were advancing Tuesday in the Sahl al-Ghab region north of the central province of Hama.

Syria's state news agency SANA says troops repelled the attack, killing and wounding dozens.

The Observatory said 11 militants were killed in Tuesday's battles.

Insurgents have been on the offensive in the northern Idlib province since March, when they captured the provincial capital. Tuesday's battles were near the town of Jisr al-Shughour, which militants captured in April.

The allied insurgent groups include al-Qaida and other Islamic militants, as well as Western-backed rebels.