Canada will push for stronger sanctions against Syria over a bloody crackdown on anti-government protesters, Prime Minister Stephen Harper says.

"Their behaviour is outrageous," Harper said Thursday during a state visit to Costa Rica.

"I think they're on a path that, frankly, is not sustainable. But we will continue to work with our allies in particular to bring diplomatic pressure to bear ... including bringing forth stronger sanctions, and that is something we will be elaborating on in the not-too-distant future."

Canada has already put sanctions on Syria that prevent the country's leaders from travelling to Canada and essentially ban trade between the two countries. But the measures are largely symbolic because Canada exports only about $60 million a year to Syria, and receives less than a tenth of that in imports.

The United States has been turning up the pressure on Syrian President Bashar al-Assad as Syrian forces have widened a brutal offensive aimed at crushing a five-month uprising against the regime. Activists say more than 2,000 people have died in cities and towns across the country.

A spokesman for U.S. President Barack Obama stopped just short Thursday of calling for Assad's ouster, but added: "We believe that President Assad's opportunity to lead the transition has passed."

Saudi Arabia and several wealthy Gulf states have withdrawn their ambassadors to Damascus in protest of the regime's killing of demonstrators. And Turkey, long a Syrian ally, has also condemned the attacks.

Trade tour continues in Costa Rica, Honduras

Earlier Thursday, Harper and Costa Rican President Laura Chinchilla announced several security and trade measures.

They include new agreements on air transportation and the exchange of tax information between the two countries, the opening of a new visa application centre in the country in September, and measures to bolster Costa Rica's police force.

The two governments are also going back to the negotiating table over their nine-year-old deal on free trade. The talks are aimed at getting rid of tariffs for agricultural and industrial goods, and broadening the agreement to cover areas such as trade in financial services.

Harper is on a four-country tour of Latin America that wraps up Friday with a stop in Honduras.