The Canadian government has issued a travel advisory in reaction to tough new U.S. anti-terrorism laws. The government is urging its citizens born in certain countries like Iraq and Saudi Arabia to think twice before entering the United States.

The advisory issued Monday focuses on a U.S. regulation adopted in September permitting authorities to closely monitor anyone born in certain countries suspected of terrorism links upon arrival in the United States.

Canada considers the system discriminatory because it targets citizens based on where they were born, said Reynald Doiron, a Canadian foreign-affairs department spokesman. "It's against basic principles on both sides of the border," Doiron said. "Canadian citizens should be exempted from that measure."

Syria, Iran, Iraq, Libya and Sudan are the countries listed in the U.S. National Security Entry Exit Registration System introduced on the first anniversary of the September 11 attacks. The system authorizes the U.S. Immigration and Naturalization Service to photograph, fingerprint and monitor the arrival and departure of visitors born in or citizens of those nations.

The Canadian travel advisory notes that people from Pakistan, Saudi Arabia and Yemen "could also attract special attention from American immigration and security authorities."

Canada's relationship with the United States already is under strain over a drawn out trade dispute about Canadian lumber exports, recent tensions over wheat exports and opposition to a unilateral war with Iraq.