The Islamic Hamas movement's administration in the Gaza Strip has arrested the leader of a radical al-Qaeda affiliated Islamic Salafi group and five of his aides, the group said in a statement on Monday.

The group, called the Army of the Nation (Jaish el-Omma), said in a statement sent to reporters that Hamas police arrested Abu Hafs al-Maqdisi, the group's leader, and five other activists of the group.

"They are toughly and harshly interrogated in Hamas prisons, with barbarian ways to torture them which miss any human considerations," said the group.

It added that a force belongs to Hamas interior security stormed the house of al-Maqdisi and kidnapped him.

"Hamas interior security seized his rifle and his private computer in addition to personal stuff," said the group. "His only accusation is Jihad for the sake of Allah and firing rockets at the Jewish settlements."

The statement said this is the fourth time that Hamas detains al-Maqdisi, adding that for each time Hamas keeps him in custody for several months.

Meanwhile, the statement said that the interior security apparatus of Hamas arrested five members of the group "right after their Amir Abu Hafs al-Maqdisi was arrested."

In recent weeks, radical militant Salafi groups intensified their attacks from the Gaza Strip on Israel and fired dozens of homemade rockets, while Hamas is trying to restore calm on the borders with Israel.