Dozens killed in Afrin clashes, as EU expresses concern at the Turkish military campaign

Dozens of Syrian combatants have been killed in three days of fighting since Turkey launched a military offensive on the northern Syrian region of Afrin, a monitor said on Monday.

Turkey's military launched a cross-border operation using war planes and artillery this weekend to back a major ground incursion launched with Ankara-backed Syrian rebels, to oust the People's Protection Units (YPG) militia from its enclave of Afrin.

More than 54 combatants have been killed in the campaign, the Syrian Observatory for Human Rights said, including 26 Kurdish fighters from the Syrian Democratic Forces (SDF), which is mostly manned by the YPG component.

Another 19 fighters from pro-Ankara rebels fighting with Turkish forces also dies.

Nine more unidentified bodies were found on the battlefield.

The civilian death toll rose to 24 over three days, the Syrian Observatory for Human Rights said. Two died as a result of Kurdish fire, while the rest were killed in Turkish shelling and air strikes.

Ankara has denied being responsible for any civilian deaths.

Turkey says the intention of its operations in northern Syria is to secure its southern border and prevent the YPG from opening a "terror corridor" between Afrin and Kurdish-held territories to the east.

The operation is highly-sensitive as Washington relied on the YPG to oust Islamic State group militants from their Syrian strongholds. The Kurdish militia now holds much of Syria's north.

In its first reaction, the US State Department on Sunday urged Turkey "to exercise restraint" and ensure the operation remained "limited in scope".

On Monday, the European Union's diplomatic chief Federica Mogherini said she was "extremely worried" by Turkey's offensive against Kurdish militia targets in Syria, saying she would seek urgent talks with Turkish officials.

"I'm extremely worried and will discuss this among other things with our Turkish interlocutors," Mogherini said after a regular meeting of EU foreign ministers where the issue was raised.

She added that she was concerned about the impact on civilians and on the UN-backed Syrian peace process.