Via JPost:

The Gaza-based militant group Jaish al-Islam [Army of Islam] has pledged formal allegiance to ISIS, according to a communiqué attributed to the group that was circulated on the Internet on Wednesday.

The communiqué in the name of Jaish al-Islam has been circulating through the Jihadi Twittersphere and Facebook, with the statement: “We, the soldiers of Jaish al-Islam in the Gaza Strip and our leader Mumtaz Dughmush, may Allah preserve him, we consider our selves to be an integral part of Wilayat Sinai [ISIS in the Sinai Peninsula]…we pledge allegiance to Abu Bakr al-Baghdadi al-Qurayshi, the Caliph to all Muslims in the House of Islam and each place where Muslims reside.”

The communiqué continues: “We swear to our brothers that, with might, we will not stop our fight against the Jews and the apostates in Gaza and in the Sinai” until the flag of the Islamic State is raised above them.

Jaish al-Islam, led by the leader of the Dughmush clan, Mumtaz Dughmush, is one of the Gaza Strip’s oldest and most powerful Jihadi-Salafi groups. The group is perhaps best known for kidnapping BBC reporter Alan Johnston in 2006 in Gaza, as well as taking part in the operation with Hamas to kidnap Israeli soldier Gilad Schalit.