Two tourists, reported to be women, have been killed in stabbings at a hotel in the popular Red Sea resort of Hurghada, Egyptian medical officials say.
At least four other people were injured and a man has been arrested.
The suspect is being questioned by police to determine his motives, the interior ministry said.
The attacker appears to have swum from a nearby public beach to gain access to the resort, officials say.
Three foreign tourists were stabbed at the same resort, renowned for its scuba diving, in January 2016 by two suspected militants from the Islamic State militant group (IS).
Initial reports said those killed on Friday were Ukrainian, but the Reuters news agency subsequently said they were Germans.
Egypt’s security forces are dealing with an Islamist uprising in the country’s Sinai Peninsula. The tourist industry has been targeted by militants in North Africa over the past few years.
A Russian passenger plane was brought down by a bomb in the peninsula in October 2015, killing all 224 people on board.
In June 2015 at least 39 people, mostly foreigners, were killed and 36 injured in an attack on a beach in the Tunisian resort town of Sousse.