The Syrian army has entered Manbij near the Turkish border, marking the return of territories held by US-backed militants to the government fold for the first time in years, an army spokesman said Friday.

The announcement came moments after the city's residents asked the Syrian government to retake Manbij following a US pledge to withdraw troops from the Arab country.

The army said it would guarantee "full security for all Syrian citizens and others present in the area."

Russia welcomed the development, with Kremlin spokesman Dmitry Peskov calling it a positive trend.

"Of course, this will help in stabilizing the situation. The enlargement of the zone under the control of government forces... is without doubt a positive trend," he said.

State-run SANA news agency said the army raised the national flag in the city which is mainly populated by Syrian Kurds. It is not clear yet whether US troops, which had a base in Manbij, remain in place or have withdrawn.

الجيش السوري يعلن الدخول الى #منبج ورفع العلم السوري فيها بعد نداء من أهلها - بيان pic.twitter.com/qCDl8vfoBi — Zaid Benjamin (@zaidbenjamin) December 28, 2018