Turkey on Tuesday warned its citizens not to visit countries where swine flu cases have been reported, an official statement said.

The statement issued by the Turkish Health Ministry said that Turkish citizens are recommended to suspend their visits to the countries hit by swine flu.

It also urged citizens to practice hygienic precautions, including washing their hands frequently or wearing masks.

The statement said the World Health Organization has labeled the flu in phase 4, which meant that it poses risk of infection from one human being to another.

No case has been encountered in Turkey, the statement added.

The Turkish Health Ministry has taken necessary precautions against the flu in accordance with Turkey's own situation and WHO recommendations.

The ministry's general director of fundamental health services Seracettin Com said from Monday on, "travelers from Mexico and its neighbors, along with Spain, are starting to be screened at our airports that are open to international air traffic."

He said the health ministry has also warned its branches across the country about the responses they should give in emergency cases related to the infection.