Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: (CNN) Dozens of men wearing military combat uniforms and armed with automatic machine guns carried out the deadly assault on a Sufi mosque in northern Sinai, Egyptian authorities said. Twenty-five to 30 attackers arrived in five SUVs at the al Rawdah Sufi mosque in Bir al-Abed on Friday. Some wore masks and at least one was carrying an ISIS flag, the state prosecutor told state-run Nile TV in a statement. They positioned themselves at the building's entrances and the front of the mosque shortly before the massive gunfire and loud explosions rang out. By the time the attackers' weapons went quiet, 305 people were dead, including 27 children, the prosecutor said Saturday. An additional 128 people were wounded.Between 25 and 30 armed men carried out the attack, officials sayAt least one attacker carried ISIS flag 
 Question:Egyptian security forces face almost daily attacks from militants with ISIS ties in northern _.

Sinai