The Islamic State of Iraq and the Levant group has advanced on Syria's northeastern province of Hasakah following deadly battles with Syrian government forces.
An activist in Hasakah, who spoke on the condition of anonymity, told Al Jazeera on Thursday that ISIL took over al-Ahdath prison and three towns after days of clashes.
"ISIL is now at the southern entrance to Hasakah city. They managed to take over the checkpoint, known as the Panorama checkpoint," he said.
The activist said that neither electricity or water had been available to residents for the past five days.
ISIL launched an attack last week on Hasakah, a city split between the Syrian government and Kurdish forces.
The UK-based Syrian Observatory for Human Rights said the government of President Bashar al-Assad sent reinforcements to Hasakah province on Thursday, where at least 27 soldiers were killed during battles.
ISIL lost 20 fighters, according to the monitor, including six who detonated their explosives near government forces in Qamishli city.
Clashes continued between government forces and ISIL as government air strikes targeted ISIL bases around Hasakah province, leaving many people injured.
Elsewhere in Syria, at least nine people were killed in government air strikes and barrel bombs, the Syrian Observatory reported.
The monitor said at least 206 people were killed on Wednesday across Syria: government soldiers, ISIL fighters and 53 civilians who perished in Aleppo suburbs.
More than 220,000 people have been killed in Syria since anti-government protests broke out in March 2011.
Source: Al Jazeera