ISMAILIA, Egypt (Reuters) - Gunmen armed with rocket-propelled grenades attacked several military checkpoints in Egypt's Sinai Peninsula on Thursday, killing seven soldiers, security sources said, defying one of the toughest security crackdowns in the country's history.
There was no immediate claim of responsibility for the attack but militants who support Islamic State, the ultra-hardline group that controls parts of Iraq and Syria, have carried out similar operations in Sinai.
Egypt is gradually recovering from years of political turmoil following the ouster of autocrat Hosni Mubarak in 2011 and foreign investors are starting to return. But the biggest Arab state still faces security challenges on several fronts.
Sinai-based militants have killed hundreds of soldiers and police since the army toppled Islamist President Mohamed Mursi in 2013 after mass protests against his rule.
That insurgency has spread to other parts of Egypt though bombing attacks in cities and towns are usually far less dramatic.
President Abdel Fattah al-Sisi, who has spearheaded an Arab initiative to create a joint military force to confront regional security challenges, says militants based next door in chaos-ridden Libya also pose a threat to Egypt.
(Reporting by Yousri Mohamed; Writing by Michael Georgy; editing by John Stonestreet)