Egyptian President Abdel Fattah al-Sisi said a deadly assault on an army checkpoint in the Sinai Peninsula was a “foreign funded operation.”

The coordinated assault killed 30 Egyptian troops on Friday near the border with the Gaza strip making it the deadliest single attack on the military in decades.

“This operation had a foreign fund to execute such an operation against the Egyptian army,” said al-Sisi, adding: “This is aimed to break the back of Egypt and Egyptians.”

Egypt closed the Rafah border crossing into Gaza, declared a three-month state of emergency and imposed an overnight curfew in the northern part of the peninsula.

No one has yet claimed responsibility for the attack, but it bore the hallmarks of the extremist group Ansar Beit al-Maqdis which has carried out several attacks on security forces.