Egyptian authorities have quarantined a student dormitory of the American University in Cairo after two U.S. students tested positive for swine flu.

Police cordoned off the dormitory in Cairo's upscale Zamalek neighborhood Monday with 234 people inside, including at least 110 students, many of them foreigners. Egyptian officials said they had placed the building under quarantine for 24 hours.

The two American students who contracted swine influenza A-H1N1 were being treated in a hospital, along with a third student suspected of having the virus.

Egyptian officials say the two Americans, both aged 23, arrived in Cairo from the United States on May 28 on separate flights. They had enrolled in summer classes at the American University in Cairo. The school has suspended classes for the rest of the week.

The new infections raise the number of swine flu sufferers in Egypt to three.

Egypt announced its first confirmed case last week involving a 12-year old girl who arrived from the United States. That case also was the first to be reported in Africa.

Egyptian authorities have installed thermal monitors at the country's airports to try to detect and isolate arriving travelers suffering flu symptoms.

Egypt also is trying to contain the spread of the H5N1 bird flu virus, which has infected at least 27 people in the country this year, more than three times the number of 2008 cases.

The World Health Organization says bird flu has killed at least 27 people in Egypt since it was first reported there in 2006.

Egypt is carrying out a controversial cull of the nation's more than 250,000 pigs in response to the swine flu problem. The World Health Organization has criticized the cull as unnecessary.