The two jihadists who attacked a French church and killed a priest on Tuesday pledged allegiance to the Islamic State (ISIS) group, a video released on Wednesday has shown. The two terrorists stormed into a church in the northern town of Saint-Etienne-du-Rouvray during morning mass Tuesday and slit the 86-year-old priest's throat at the altar before being gunned down by police. Another man was left seriously injured in a hostage drama, while three nuns and a worshipper escaped unharmed. One of the attackers has been identified as French jihadist Adel Kermiche , 19, who was awaiting trial on terror charges and had been fitted with an electronic tag despite calls from the prosecutor for him not to be released. Sources close to the investigation said they found an identity card belonging to one Abdel Malik P., also 19, at Kermiche's home, who they believe is the second attacker. They said Abdel Malik "strongly resembles" a man hunted by anti-terrorism police in the days before the attack over fears he was about to carry out an act of terror. In a video posted Wednesday by the news agency Amaq which is affiliated with ISIS, two bearded men, calling themselves Abu Omar and Abu Jalil al-Hanafi, hold hands as they swear "obedience" to ISIS leader Abu Bakr al-Baghdadi. Meanwhile the French government, already under pressure after the recent Bastille Day terrorist attack in Nice, faced more questions over security weaknesses after it emerged Kermiche was known to anti-terror investigators. Paris prosecutor Francois Molins said Kermiche twice tried to travel to Syria under a false identity. After his latest arrest in Turkey in May 2015, he was held in custody until March this year when he was released and fitted with the electronic bracelet. The attack in Normandy is the third in two weeks in France and Germany in which jihadists have pledged allegiance to the group, increasing jitters in Europe over young, often unstable men being lured by ISIS propaganda and calls to carry out attacks in their home countries. AFP contributed to this report.