At least 235 people were killed in an attack Friday around a mosque in the northern Sinai Peninsula, Egyptian state television reported, making it one of the deadliest terrorist attacks ever in Egypt.

The report also said more than 100 people were injured when a bomb exploded near a mosque during Friday prayer, and gunmen then opened fire amid the mayhem.

Although nobody has so far claimed responsibility for the attack, there is a possibility that the Islamic State extremist group was involved.

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"It is a cowardly attack that aims to destabilize the (country's) unity, spread bitterness, and make us doubt our abilities," Egyptian President Abdel Fattah el-Sisi said.

While addressing the nation, he added, "However, this attack will do nothing but make us stronger and more persistent to combat terrorism," according to local media Egyptian Streets.

The president further promised that Egypt's army and police will maintain control and take appropriate security measures. "We will respond to this terrorist attack vigorously," he said.

Reuters news agency reported, citing eyewitness accounts provided to Egyptian newspaper Al-Masry Al-Youm, that an explosion occurred near the Al-Rawdah mosque in the center of the town of Bir al-Abd, after which people fleeing the area were attacked by gunmen presumed to be Islamic militants.

There have been numerous terrorist incidents in recent years on the Sinai Peninsula carried out by Islamic militants enraged by the imprisonment of Mohamed Morsi, the former Egyptian president and leader of the national branch of the Muslim Brotherhood.

Morsi was deposed in a July 2013 military coup led by el-Sisi, who then headed the military and is now the president.

In a Twitter post, U.S. President Donald Trump called the incident a "horrible and cowardly terrorist attack on innocent and defenseless worshipers in Egypt."

"The world cannot tolerate terrorism, we must defeat them militarily and discredit the extremist ideology that forms the basis of their existence!" Trump continued.