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: ISIS militants besieging a Palestinian refugee camp in Syria's capital have savagely beheaded the leaders of a Hamas-linked group opposed to President Bashar Assad, it has been claimed. Having seized control of up to 90 per cent of the Yarmouk camp in south Damascus, the jihadis posted gruesome images showing the severed heads of two alleged members of Aknaf Beit al-Maqdis online. Like ISIS, the Palestinian group has declared Israel its sworn enemy, although its presence in Yarmouk has until now been to defend the camp's 18,000 residents from a crippling two year siege carried out by the Assad regime.Rampaging ISIS militants have seized up to 90 per cent of Yarmouk camp100 Palestinian refugees have been killed or kidnapped since WednesdayTwo members of a Hamas-linked group were beheaded, witnesses saidNow Gaza-based leaders have sworn bloody revenge on ISIS terrorists 
 Question:ISIS stormed the camp on Wednesday, marking the terrorist's deepest foray yet into _ - the Syrian capital and base of President Assad's government.

Damascus