Montreal  - The Canadian government has slammed the door on Roma asylum seekers from the Czech Republic and Mexicans fleeing the country's violent drug wars by reimposing visas for citizens of both countries travelling to Canada.

The measures took effect at midnight (0400 GMT Tuesday), the office of Immigration Minister Jason Kenney announced Monday.

Canada immediately received swift rebukes from the Czech and Mexican governments.

"The Czech authorities perceive this decision as one-sided on the part of Canada and inadequate and unfriendly in the context of the long-term good relations between the two democratic countries," the Czech embassy in Ottawa said in a statement.

The Czech government planned a special meeting Tuesday to discuss appropriate measures in response to Canada, the statement said.

"The government of Mexico regrets the decision by the government of Canada, announced today, to impose visas on Mexican nationals travelling to Canada as tourists," said a release issued late Monday.

It is the second time that the Canadian government has felt forced to impose visas on Czechs following an influx of refugee claimants from the country.

In 1997, following a similar influx of Roma refugee claimants, Canada reimposed visas on Czech citizens less than a year after lifting visa requirements.

In October 2007, after intensive lobbying by the European Union, Canada lifted the visa requirement on the Czech Republic. Since then, nearly 3,000 Czech nationals have made refugee claims, compared with fewer than five in 2006, Kenney said.

While Canada does not compile statistics on the ethnicity of refugee claimants, most asylum claims from the Czech Republic are believed to have been made by Roma claiming endemic discrimination and persecution.

Canada's Immigration and Refugee Board, an independent tribunal that examines asylum requests, has accepted 118 Czech asylum applications since late 2007, determining that the applicants had "a well-founded fear of being persecuted for reasons of race, religion, nationality, political opinion or membership of a particular political group."

Kenney said that despite a relatively high acceptance rate, more than half the claims made by people from the Czech Republic are abandoned or withdrawn before a final decision is made on their status, suggesting that many may be making false claims.

"In addition to creating significant delays and spiralling new costs in our refugee programme, the sheer volume of these claims is undermining our ability to help people fleeing real persecution," Kenney said in a statement.

He said the Czech Republic became the second-leading source country for refugee claims, ahead of such war-ravaged countries as Somalia and Afghanistan.

"All too often, people who really need Canada's protection find themselves in a long line, waiting for months and sometimes years to have their claims heard," Kenney said. "This is unacceptable."

Refugee claims from Mexico have almost tripled since 2005, making it the top source country of claims for refugee status in Canada, Kenney said.

Over the first two days of the restriction, people travelling to Canada from either country can apply for entry on arrival at a border crossing. Beginning Thursday, visas will be required. (dpa)