OTTAWA (AP) – President Barack Obama stepped cautiously in his first foreign trip Thursday, refraining from asking Canada to rethink its plans to withdraw troops from Afghanistan and saying changes to the North American Free Trade Agreement can wait.

The new U.S. president was cheered by crowds in the snowy Canadian capital and responded by declaring “I love this country” at a news conference. Later, he stopped at a downtown market, where he delighted onlookers by shopping for gifts for his family.

In the news conference with Canadian Prime Minister Stephen Harper, Obama acknowledged that he has said NAFTA does too little to protect U.S. workers and the environment. Canada, the United State’s largest trading partner, is leery of changes to the deal, and Obama said robust trade helps both nations.

Noting that NAFTA has side agreements on labor and the environment, he added, “If those side agreements mean anything, then they might as well be incorporated into the main body of the agreements so that they can be effectively enforced.” He said he hopes there will be a way to do so “that is not disruptive to the extraordinarily important trade relationships” between the U.S. and Canada.

Both leaders said that as economies around the world face crises, it’s important for the U.S. and others to resist calls for protectionism. Obama made his sharpest criticisms of NAFTA last year while campaigning for the Democratic nomination in hard-hit industrial states where many people blame the trade deal for robbing the U.S. of manufacturing jobs.

Harper and Obama also announced an agreement to begin a clean-energy dialogue. Obama said it will “advance carbon-reduction technologies,” which could slow global warming. He said it also will “support the development of an electric grid that can help deliver the clean and renewable energy of the future to homes and businesses” in both countries.

Harper said he was pleased that Canada now has a North American partner to help provide leadership on climate change.

Turning to border security and fighting terrorism, Harper said any threat to the United States is a threat to his country, too.

The prime minister said Canada has made “significant investments” in security and in border protection since the Sept. 11, 2001, terrorist attacks.

But he said there’s a “real challenge” in increasing border security in a way that doesn’t limit commerce and social interaction.

Harper, alternating between English and French, said Obama’s election “launches a new chapter in the rich history of Canada-U.S. relations.”

Obama returned the warm words, saying he has top aides and a brother-in-law from Canada. “I love this country and think that we could not have a better friend and ally,” he said.

After his stop at the market, Obama met with Canada’s opposition leader, Michael Ignatieff. Before heading back to Washington, the president thanked U.S. Embassy workers who had gathered in an airport hangar, telling them they are his ambassadors here.

He said he had chosen Canada for his first international trip to underscore the relationship between the two countries, and he talked about similarities. “As I was wandering around, I thought I might be in Chicago. The weather’s the same,” he said.

AP-ES-02-19-09 1726EST