Egypt stopped 61 Canadian Shia Muslim pilgrims from entering the country and decided to hold them at Cairo airport until their onward flight, security officials said on Sunday.

The Canadians landed in Egypt from Iraq to complete a pilgrimage to Shia sites in the region, but were kept out on the orders of security authorities, said airport security officials who gave no further explanation. Canadians are usually allowed into Egypt with a visa bought upon arrival.

The Department of Foreign Affairs is in contact with the group and is monitoring the situation, a spokeswoman told CBC News, though she noted Egypt, like any country, is free to determine who can enter. 

A spokesman for Canadian Foreign Minister John Baird said Ottawa would react later on Sunday.

The government of Egypt, an overwhelmingly Sunni Muslim nation, has long been criticized for discriminating against the country's small Shia community. Egypt's official Islamic establishment has previously warned against the spread of Shia beliefs.

The U.S. State Department's religious freedom report for 2012 said the government "continued to harass" Shias.

In June, four Egyptian Shias were beaten to death by a mob, a lynching blamed partly on sectarian passions whipped up by ultra-orthodox Salafist Muslim allies of President Mohammed Morsi, who was deposed by the army a few weeks later.

The Shia denomination emerged in the earliest days of Islam from a dispute over who should lead the Muslim community after the death of the Prophet Mohammad. The Shias believe leadership should have passed to Ali, the prophet's son-in-law, and his descendants.