Security officials in Egypt say gunmen armed with rocket-propelled grenades have killed at least 20 guards near the border with Libya.
Officials say the attack Saturday took place at a border guard post in Wadi al-Gadid. Egypt's state news agency MENA said three of the attackers were killed.
A similar attack in the same area a few months ago killed at least five border guards.
Egyptian officials repeatedly have warned that violence plaguing Libya could spill over into Egypt.
More than three years after the 2011 civil war that toppled dictator Moammar Gadhafi, Libya has been sliding deeper into turmoil. Rival brigades of former rebels are battling for political and economic power.
Smugglers often use Egypt's borders with Libya and Sudan to transport weapons to Egypt, which is facing an Islamist insurgency based in the Sinai Peninsula near Israel.