Eighteen civilians have died in three days in northwestern Syria’s Afrin region, ever since Turkish troops entered the region on Saturday, Reuters reported on Monday, quoting the Syrian Democratic Forces. Turkey claims the offensive targets the United States-backed Kurdish militia YPG, or Syrian-Kurdish People’s Protection Units.

The Syrian Democratic Forces, which includes the YPG militia, said 23 people have been injured in the offensive.

Turkey’s President Recep Tayyip Erdogan said on Monday that his troops would not “step back”, BBC reported. “We are determined, Afrin will be sorted out,” he said in a live television broadcast.

Turkish troops captured a number of villages in the region on Monday, and continued to shell targets. Ankara said it would swiftly crush the YPG fighters who control the region.

France has called for an emergency meeting of the United Nations Security Council to discuss the developments. The United States has already said it is concerned about the situation.

Turkey considers YPG a terrorist organisation as it opposes the Kurds’ push for a separate nation. Washington’s support for the YPG has upset Turkey, which is otherwise a key US ally in the North Atlantic Treaty Organisation.

In a bid to assure the international community, Turkish Deputy Prime Minister Mehmet Simsek said on Monday: “Our investors should be at ease, the impact will be limited, the operation will be brief and it will reduce the terror risk to Turkey in the period ahead.”

Meanwhile, pro-Kurdish protestors staged demonstrations in Ankara and Istanbul against Turkey’s operations in Afrin. At least 12 protestors were reportedly detained in Istanbul.