BEIRUT -- Militants have captured two villages from Syrian government forces and their allies in the northern province of Aleppo after days of heavy fighting that left scores of fighters dead, Syrian activists said Saturday.

The Britain-based Syrian Observatory for Human Rights said the four-day offensive by different militant groups, including the al-Qaida-affiliated Nusra Front, killed 86 troops and pro-government gunmen, including 25 members of Lebanon's Hezbollah group.

The Observatory and the Local Coordination Committees, both of which monitor the conflict through networks of local activists, say militants now control the villages of Zeitan and Khalsa, south of Aleppo city.

Nusra Front and its allies have launched several offensives south of Aleppo in recent months, inflicting heavy casualties among pro-government forces. Government forces have meanwhile closed in on rebel-held parts of the city, which have been under daily bombardment.

"The situation is very good," a Nusra Front fighter in southern Aleppo told The Associated Press by telephone. The fighter, who goes by the name of Abu al-Hassan al-Muhajer, confirmed that the militants have captured the villages.

Hezbollah issued a statement in Beirut on Saturday saying it lost a number of "martyrs" in "direct and fierce confrontations with terrorist organizations." The group denied Arab media reports that said Hezbollah fighters were killed in clashes with Assad's forces and struck by Syrian government warplanes, saying its relations with the Syrian army and other allies are "strong."

Hezbollah has sent thousands of fighters to Syria to back President Bashar Assad's forces and has played a key role in a string of government victories.

In Aleppo city, shelling killed seven people and wounded more than a dozen in the predominantly Kurdish neighbourhood of Sheikh Maqsoud. The area is under the control of the main Kurdish militia, the People's Protection Units, or YPG, which has clashed with Syrian insurgents as well as the Islamic State group.

In Damascus, meanwhile, Assad met with Russia's Defence Minister Sergey Shoygu on Saturday, Syrian state news agency SANA reported, without providing further details.

Russia has been a key ally to Assad throughout the civil war and began carrying out airstrikes to bolster his forces last September.

Five years of conflict have killed more than a quarter-million people in Syria.