At least 23 Egyptian soldiers were killed and another 26 injured when suicide car bombs tore through two military checkpoints in North Sinai. <br/><br/>Security sources said, the two cars blew up at two checkpoints outside of a military compound just south of Rafah, on the border with the Gaza Strip.<br/><br/>In a statement Islamic State said its fighters targeted the compound because the military was preparing to launch operations against the Sunni Muslim militant group from there.<br/><br/>The attack is the most severe in Sinai since at least July 2015, when Islamic State militants assaulted simultaneously a slew of checkpoints and military sites around North Sinai. At least 17 soldiers were killed, according to an official tally.<br/><br/>Yesterday's bombings present a challenge for general-turned-president Abdel Fattah al-Sisi, who describes Islamist militancy as an existential threat and himself as a bulwark against extremism in a region beset by violence and war. <br/><br/>Security sources described yesterday's attack as a coordinated strike, with car bombs blowing apart checkpoints as gunmen in four-wheel drive vehicles shot down soldiers running for cover. <br/><br/>Militants in armoured vehicles meanwhile fired rocket propelled grenades at a military site just beyond the checkpoint, the sources said.<br/><br/>Responding to the Sinai attack, Prime Minister Sherif Ismail stressed the need for countries to unite against those who support terrorism and to dry up their sources of funding, an allusion to Qatar.<br/><br/>Egypt, Saudi Arabia, the United Arab Emirates and Bahrain broke diplomatic relations with Qatar last month and are now boycotting the Gulf Arab state, which they accuse of supporting terrorism and allying with regional foe Iran. Qatar denies this.