Islamist Sunni militants are threatening to advance on Iraq’s capital, pushing to within 100 kilometers to the north, after seizing several other key cities in a blow to the country’s Shi’ite-led government.

A spokesman for the Islamic State in Iraq and the Levant (ISIL), an al-Qaida offshoot, said in a message posted Thursday that the militants also want to take the city of Karbala, home to one of the holiest sites for Shi’ite Muslims.

Al-Jazeera reported the ISIL was also marching toward Sammara, home to one of the most venerated Shi’ite places of worship in Iraq.

In another development, officials said Kurdish forces have taken control of the disputed northern city of Kirkuk. The city is in an area that Kurds want to incorporate into their autonomous region, against the wishes of the central government.

“The whole of Kirkuk has fallen into the hands of peshmerga,” said Jabbar Yawar, a spokesman, referring to the Kurdish forces. “No Iraqi army remains in Kirkuk now.” 

Yawar told Iraqi satellite channels that government soldiers had abandoned 300,000 to 400,000 weapons and a number of planes when they withdrew from Iraq’s Mosul, which the militants seized Tuesday.