The move by Ansar Bayt al-Maqdis, based in Egypt’s restive Sinai peninsula, highlights Islamic State’s widening influence in the region.

“I’m sending a message to our people in Egypt, what are you waiting for? Your honor was violated and the blood of your sons was shed at the hands of this tyrant and his soldiers,” said the statement, read by a man who identified himself as part of the group’s information department. The reference apparently was to Egyptian President Abdel-Fattah El-Sisi, who, as defense minister in July 2013, led the ouster of Islamist predecessor Mohamed Mursi.

The clip was posted early today on a Twitter account that identifies itself as Ansar Bayt al-Maqdis’s official mouthpiece and is posted on a website used by Islamists. The authenticity of the account couldn’t be independently verified. A U.S.-led coalition has been attacking Islamic State positions in an effort to halt the group’s advances, after it wrested control of large areas of Iraq and Syria.

Regional Influence

Ansar Bayt al-Maqdis has claimed responsibility for many of the attacks against police and army forces in Egypt’s Sinai peninsula that have increased since Mursi was toppled. El-Sisi said Egypt faces an “existential threat” from Sinai-based militants following an Oct. 24 attack that killed more than 30 troops, and ordered a stepped-up campaign against them.

Ansar Bayt al-Maqdis’s decision to join ranks with Islamic State is a sign of the latter’s growing regional influence and may encourage other militant groups in the region to follow, according to Anthony Skinner, head of analysis for the Middle East and North Africa at U.K.- based forecasting company Maplecroft.

“There had been very strong competition between the Islamic State and al-Qaeda splinter groups in the region and the move represents a decisive shift towards the Islamic State,” Skinner said in a phone interview. “This will also enhance Ansar Bayt al-Maqdis’s recruitment appeal for the disillusioned and increasingly radicalized elements of the Egyptian society.”

Border Evacuation

The Egyptian army recently evacuated Sinai residents from homes along the border with the Gaza Strip, controlled by Islamist Hamas militants.

In a statement posted on its Twitter account late yesterday, Ansar Bayt al-Maqdis vowed to avenge evacuated Sinai residents. “We will not stand idly by in the face of this aggression and will soon take revenge,” it said in the statement.

The government has blamed much of the violence in Egypt on the Muslim Brotherhood, which denies the allegation and says it’s committed to peaceful protests against the military takeover.

Ansar Bayt al-Maqdis’s hookup with Islamic State increases the risk that the militant group may attack foreign groups or entities in Egypt, Skinner said.

“We might witness a shift towards large-scale indiscriminate attacks against foreign interests to take revenge for airstrikes by the U.S. and the broader alliance in Syria and Iraq, and also to discourage foreign investment in the country,” he said.