The assailant has been arrested and is being questioned to determine his motives, the ministry said in a statement.
Their nationalities were not immediately clear, but at least one of the tourists is a dual Ukrainian-Russian national, according to Russian media citing the consulate in Egypt.
The ministry said the assailant swam to the beach before attacking the tourists.
In January 2016, three tourists in Hurghada were wounded in a stabbing attack by two assailants with apparent ISIS group sympathies.
Hurghada is one of Egypt's most popular beach resorts, especially with Ukrainians and European tourists.
An ISIS group bombing of a Russian airliner carrying holidaymakers from a south Sinai resort in 2015 killed all 224 people on board and decimated the country's tourism sector.
Russia suspended all flights to Egypt in response and has yet to resume them.
ISIS has been waging a deadly insurgency based in the north of the Sinai Peninsula that has killed hundreds of policemen and soldiers.