A Jihadist group that murdered 26 people and injured a further 60 this morning in combined bomb and mortar attacks has declared its allegiance to the Islamic State of Iraq and Syria (ISIS).

The extremist group used Twitter to announce in Arabic that IS promised “a new dawn raising the banner of monotheism”, the BBC report.

The group has previously denied allying itself with IS but have now said the attacks were “an extensive simultaneous offensive for the soldiers of the caliphate”. A car bomb was detonated outside a military base while mortars were simultaneously fired at the stronghold, causing serious damage to buildings and burying soldiers under the fallen masonry.

Three locations were targeted, the North Sinai capital el-Arish among with nearby towns of Sheik Zuwayid and Rafah which is a regular site for violence given its location on the border with Gaza and the crossing there.

Ansar Beit al-Maqids has previously denied allying itself with IS, which has declared a cross-border Caliphate in Syria and Northern Iraq where the conflict still rages.

The group, which has several factions, is no stranger to launching attacks against police and the army in Sinai in recent years. Initially inspired by al-Qaeda, took to Twitter last week to dismiss reports it had pledged allegiance to the IS leader, Abu Bakr al-Baghdadi.

Making no reference to the earlier communication, the group, whose name translates to ‘Champions of Jerusalem’ said Baghdadi had been chosen by God to set up a new caliphate.

The whereabouts of the IS leader remain unclear after Iraqi authorities reported last Sunday that he had been wounded in an air strike by US led fighter jets.

But despite these claims, the group promised to “listen and obey” him and appealed to Muslims everywhere to pledge allegiance.

The US State Department condemned the attack, saying: “The United States remains steadfast in its support of the Egyptian government’s efforts to combat the threat of terrorism in Egypt as part of our continuing commitment to the strategic partnership between our two countries.”

The country is leading a coalition effort in the region to provide air support for those forces trying to defeat IS on the ground.

Along with air strikes and the delivery of aid, President Barak Obama said that the battle against IS was entering a “new phase” with 1,500 US troops being deployed to Iraq in a non combat capacity as advisors.

Egypt has been plagued by attacks and fractured groups since the military overthrew the Islamic President Mohammed Morsi in July 2013. His downfall encouraged militants to step up the violence on Egyptian security forces.

The latest pledge of loyalty by Ansar Beit al-Maqdis is a worrying sign of the growing appeal the terrorist jihadist group has with other militant groups.

Last month, dozens of troops were killed in an attack on an army checkpoint in the same region, although no group claimed responsibility. But it led President Abdel Farrah as-Sisi to give the military extra powers in order to combat the militant groups in the peninsular.

The group has called on Egyptians to rise up against President Sisi, who led the overthrow of previous President Morsi who was accused of trying to organise an ‘Islamic coup’ whilst in office, giving himself huge swathes of power including over the judiciary.