BEIRUT — Islamic State militants fighting in Syria on Friday reached the southern gates of the predominantly Kurdish northeastern city of Hassakeh amid intense air raids and shelling, Syrian activists and the extremist group’s radio station said.

The push came as the U.N. Security Council expressed “outrage” at all the attacks against civilians in Syria, including those involving shelling and barrel bombs – bombings that have reportedly been used extensively in Aleppo, Syria’s largest city, and other areas in recent days, leaving many civilians dead.

The Islamic State group has been attacking Hassakeh city since May 30, facing stiff resistance from government forces. The city has been split between government forces and Kurdish fighters who have been attacking IS positions elsewhere in the province.

IS radio station Al-Bayan said the militants were two-thirds of a mile from the southern entrance in the city, claiming they have killed dozens of soldiers.

The Observatory and the Local Coordination Committees say government warplanes repeatedly attacked IS forces near Hassakeh on Friday. The Observatory said 71 government troops as well as 48 IS fighters were killed in Hassakeh over the past week.

Members of the Kurdish militia known as the People’s Protection Units, or YPG, have not joined the battle in the city so far, but one of its commanders, Polan Jan, said in comments posted on the group’s official Facebook page that “we will not allow Daesh or others to control our Kurdish city of Hassakeh.” He used an Arabic acronym to refer to the group.

YPG have been advancing in northern Syria against IS fighters for weeks, under the cover of the U.S.-led coalition that is bombing IS positions.

A press statement issued by the U.N. Security Council on Friday also condemned increased terrorist attacks resulting in numerous casualties and destruction carried out by the Islamic State group, al-Qaida’s Syrian branch called the Nusra Front and other militant groups.