DAMASCUS -- The Kurdish-led Syrian Democratic Forces (SDF) will continue to fight against the Islamic State (IS) militants who refused to surrender in Syria's northern city of Raqqa, a Kurdish spokeswoman was cited by Kurdish activists as saying Monday.

Jihan Sheikh Ahmad was cited as saying that the SDF, which is led by the Kurdish YPG and heavily backed by the US-led coalition, launched a day earlier the last stage of the battle in Raqqa, which is to eradicate the foreign IS militants, who refused to surrender, unlike the local militants who surrendered themselves to the SDF.

This comes a day after a deal was reached between the SDF-led Raqqa Civil Council and tribesman in Raqqa for the evacuation of civilians and local IS militants from Raqqa.

Kurdish activists said a total of 275 IS fighters surrendered over the past 24 hours to the SDF, while as many as 3,500 civilians have evacuated Raqqa over the last week.

Now, an estimated number of 300 foreign IS militants and few members of their families are still in Raqqa, with the SDF pushing over to eradicate them before declaring the city IS-free.

Jihan, the spokeswoman, said the SDF fighters are continuing to advance in Raqqa, mopping up the city from six directions. She added that the SDF fighters are expected to capture the neighborhoods of Andalus and Matar in the city.

Meanwhile, the US-led coalition said the aerial bombardment of Raqqa will continue on the areas that are still controlled by IS in the city.

IS militants declared Raqqa as their capital in 2014, after announcing their self-styled caliphate.

Tens of civilians have died during the intense battles as well as in the airstrikes of the US-led anti-terror coalition since the operation against IS in Raqqa started four months ago.

On Sept. 7, the Syrian Observatory for Human Rights said as many as 978 civilians had been killed in three months by the US-led airstrike and the shelling on Raqqa.