A general of Iran's Islamic Revolutionary Guard Corps (IRGC) has been killed while "on a mission" in Syria, Iranian state media reported on Tuesday.

"General Abolfazl Alijani, a member of the IRGC's ground forces who was on a mission in Syria as a military adviser, was martyred on Sunday," the state broadcaster said on its website.

It described Alijani as a "defender of the sanctuary", a term used for those who work on behalf of Iran in Syria or Iraq, without providing more details of the attack in which he was killed.

Iran says it has deployed its forces in Syria at the invitation of Damascus and only as advisers.

In early August, funeral processions were held in Tehran and other Iranian cities for five IRGC members killed in Syria several years ago, after their bodies were recovered and identified through DNA testing, Iranian media reported.

Back in March, the Guards said that an Israeli attack in Syria killed two of its officers, warning that Israel "will pay for the crime."

Israel has carried out hundreds of air strikes inside Syria in recent years, targeting government positions as well as allied Iran-backed forces and fighters of Lebanese Shiite militant group Hezbollah.

While Israel rarely comments on individual strikes, it has acknowledged mounting hundreds of them since 2011.

The Israeli military has defended them as necessary to prevent its arch-foe Iran from gaining a foothold on its doorstep.

Iran and Israel have been engaged in a years-long shadow war, with the Islamic republic accusing its "sworn-enemy" of carrying out sabotage attacks against its nuclear sites and assassinations of key figures, including scientists.

The Islamic Revolutionary Guards Corps is the ideological arm of the Iranian military and is blacklisted as a terrorist group by the United States.

US concerned

Washington is "deeply concerned" about a recent flare-up of violence along Syria's northern border with Turkey, a State Department spokesman said Monday.

"The United States is deeply concerned about recent attacks along Syria’s northern border and urges all parties to maintain ceasefire lines," said spokesman Ned Price, days after increased bombardments in the area reportedly killed at least 21 civilians -- including children.

"We deplore the civilian casualties in Al-Bab, Hasakah, and elsewhere," said Price, adding that the United States remained committed "to ensure the enduring defeat of ISIS and a political resolution to the Syrian conflict."

The recent bloodshed came against a backdrop of increased tensions pitting the Kurdish-led Syrian Democratic Forces (SDF) against Turkish troops and their Syrian proxies.

On Friday, Kurdish authorities said that a pre-dawn strike by a Turkish drone hit "a training centre for young girls" in the Shmouka area near Hasakeh in the northeast, killing four children and wounding 11.

The Britain-based Syrian Observatory for Human Rights, a war monitor with a broad network of sources on the ground, confirmed the toll.

In Al-Bab, a town under the control of Syrian factions loyal to Ankara, "artillery fire on a market by pro-regime forces killed 17 civilians -- including six children -- and wounded another 35," the Observatory said.

An AFP correspondent said the strike on the town near the Syria-Turkey border had ripped through a market, describing it as a jumble of body parts, strewn vegetables and mangled handcarts.