Islamic State loses main supply route to Turkey

Syrian rebels seized control of the Islamic State group's main supply route to Turkey on Thursday, in a new blow to the militant group.

"Rebel factions and Islamists took control of the northeast of Al-Rai," a town occupied by IS on the border between Syria and Turkey, the London-based Syrian Observatory for Human Rights said.

"This is the main and one of the last crossing points with Turkey."

Rebels entered al-Rai following two days of intense clashes, observatory director Rami Abdel Rahman told AFP.

"Al-Rai was where they mainly smuggled in jihadists, whereas Halwaniyeh is reserved for top commanders", Abdel Rahman confirmed, adding the militants still held a crossing point further east.

The Islamic State group has suffered major blows as Iraqi and Syrian forces recaptured territories in each respective country.

IS militants lost 18 villages in the northern Aleppo province in recent days to Russian-backed Syrian forces.

They also lost the ancient city Palmyra to the regime, which they controlled since May last year.

Meanwhile in Iraq, coalition officials estimate IS has lost more than 40 percent of its territory as US-backed Iraqi forces continue the offensive into the militant group's areas.

More than 270,000 people have been killed and millions more have fled their homes since the conflict in Syria began, triggering the world's worst humanitarian refugee crisis since the Second World War.

Agencies contributed to this report