A jihadist group with ties to the Islamic State has claimed responsibility for a mortar attack on a Hamas base in the Gaza Strip.

The group, calling itself 'Supporters of the Islamic State of Iraq and Syria (IS, formerly ISIS/ISIL),' said in an online statement that it fired mortar rounds at a base used by the Ezzedine al-Qassam Brigades (Hamas' armed wing) in Khan Yunis, southern Gaza, on Friday.

Witnesses told AFP they heard explosions close to Khan Yunis.

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It follows an attack earlier this week, which targeted Hamas’ security headquarters in Gaza. That assault took place after radical Islamists issued a threatening message, calling for the release of prisoners.

It comes amid rising tensions between Hamas as Islamic State supporters in the Gaza Strip.

The attack followed the arrest of a Salafist leader by Hamas last month. The organization claimed he was an ISIS supporter who holds vast swathes of territory in Syria and Iraq.

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Dozens of other Salafi jihadists affiliated with the Islamic State were also arrested, sources in the Gaza Strip told the Jerusalem Post. They added that the arrests came following a series of bombings carried out by the Salafi jihadists in recent weeks.

Salafi jihadists also issued a warning to several top Hamas security officials responsible for the crackdown.

Earlier this week, Hamas demolished a mosque used by Islamic State supporters in Deir el-Balah. Hamas said the mosque was actually a tent which was used by the extremists as a meeting venue.

Although Gaza jihadists have pledged allegiance to ISIS in the past, the group has not officially confirmed that it has a presence there.