Two US students at the American University in Cairo have been diagnosed with swine flu, while a third case is suspected and a dormitory of about 140 other students has been quarantined, the university said on Monday.
"There are two American students who came here on May 28 and the ministry of health has confirmed that they are sick with the A(H1N1) virus," university spokeswoman Rehab Saad told AFP.
The two students are being treated in hospital along with a third suspected infected American, Saad said, adding that their dormitory on the central Cairo island of Zamalek had been placed under quarantine.
"The dorm of around 140 has been quarantined for 24 hours, the ministry of health is taking samples and the results are expected soon," Saad said.
The latest cases mean Egypt now has a total of three confirmed swine flu sufferers and one suspected. The first confirmed case was a 12-year-old girl who travelled from the United States last week and became Egypt and Africa's first case of swine flu.
The two American students confirmed with flu are a man and woman aged 23 who came to Cairo to take summer classes, Egypt's state news agency MENA quoted the health ministry as saying.
The woman arrived from New Jersey via New York and London, and the man from Florida via New York, the ministry said.
Extra police were deployed outside the dorm where mask-wearing ministry officials could be seen coming and going, an AFP photographer said.
Egypt, the most populous Arab country, began a controversial cull of its estimated 250,000 pigs after initial reports of swine flu outbreaks in other countries. More than 150,000 have been culled so far, according to Egyptian media.
The World Health Organisation (WHO) has said the drastic measure is not scientifically justified.
The authorities have stepped up checks of travellers at airports, quarantining suspected cases in makeshift centres.
Egypt is already battling the deadly H5N1 strain of bird flu, which has killed 27 people since it was first reported in 2006.
Swine flu has now spread to 73 countries with 25,288 people known to have been infected and 139 to have died since the disease was uncovered in April, the WHO said on Monday.