Foreign Affairs Minister John Baird urged Canadians and diplomats in the Middle East and North Africa to exercise “a higher degree of caution” after the United States issued a worldwide travel alert Friday, citing an unspecified al Qaeda threat.

The U.S. closed 21 embassies and consulates from Mauritania to Afghanistan for the weekend, warning travellers and citizens in the Muslim world of a potential terrorist attack in the Arabian Peninsula.

"It's not for me to discuss the nature of the elevated risk that causes them (the Americans) to take these decisions," Baird said Friday.

"Having said that, when a close friend and ally has made this determination, obviously at a bare minimum it puts us at elevated risk, and we're encouraging a higher degree of caution."

He said Canada is not currently planning to close any diplomatic missions on Sunday, a regular business day in Muslim countries.

"Obviously in the run-up between now and Sunday, we'll continuously review the situation and take any action that we feel that is in the best interests of Canada,” Baird said.

The U.S. State Department says it has information to suggest that al Qaeda-affiliated organizations “continue to plan terrorist attacks both in the region and beyond, and that they may focus efforts to conduct attacks in the period between now and the end of August.”

U.S. officials singled out Yemen, considered to be the home of al Qaeda's most dangerous offshoot.

The U.S. travel alert warns that terrorists may target both “official and private interests,” including public transportation systems and “other tourist infrastructure.”

Baird said his ministry is monitoring the situation carefully.

"Most fair minded Canadians, when they see what the United States are doing would want to realize things are at an elevated risk and want to ensure a higher degree of caution,” he said.

With files from The Canadian Press and The Associated Press