Suspected Islamic State militants on Sunday attacked six checkpoints in the turbulent north of Egypt's Sinai Peninsula, killing six soldiers and wounding 37, according to security and hospital officials.
The officials said the near-simultaneous attacks took place at and around the town of Sheikh Zweid, with dozens of militants using heavy machine guns and mortars.
Apache helicopter gunships were called in to repel the attackers, said the officials.
An army statement said 24 of the attackers were killed and two SUVs they used were destroyed.
The area was being combed by army troops in pursuit of the militants, said the statement.
The officials spoke on condition of anonymity because they were not authorised to speak to the media.
Egyptian security forces have for years battled militants in northern Sinai, which borders the Gaza Strip and Israel.
But the insurgency there has gained momentum after the Egyptian military ousted an elected Islamist president in 2013.
The insurgency is led by a local affiliate of the Islamic State group.