Image copyright AFP/Getty Image caption NAFTA negotiators say they are making progress but key differences remain

Officials from the US, Canada and Mexico say they have made progress in tense negotiations on the North American Free Trade Agreement (Nafta).

Their remarks concluded the latest round of talks, the second-to-last before the negotiations are supposed to end in March.

President Donald Trump has threatened to withdraw from the treaty, which governs more than $1 trillion in trade.

A Mexican official said the discussions are at a "much better" point.

All three sides agreed to language governing anti-corruption during the latest round, while making progress on customs and food sanitation issues.

"We are at a much better moment," Mexican Economy Minister Ildefonso Guajardo said at a press conference in Quebec, Canada.

Analysts had described this meeting - the sixth since August - as a make-or-break moment for the deal.

Officials have said they want to finish negotiations before elections get under way in Mexico and the US later this year.

Image copyright AFP/Getty Image caption NAFTA governs more than $1tn in trade

The sides remain far apart when it comes to some key questions, such as a US demand that cars have a higher proportion of parts made in the US to fall under NAFTA's tariff-free rules.

US Trade Representative Robert Lighthizer said officials are starting to discuss those areas, but the talks remain slow-going.

"We owe it to our citizens, who are operating in a state of uncertainty, to move much faster," he said.

Mr Lighthizer did offer some reassurance about future rounds, however.

"We are committed to moving forward," he said. "I am hopeful progress will accelerate soon."

Trade tensions

The Montreal gathering was the sixth meeting since Mr Trump requested to renegotiate the deal last year.

His action followed through on promises made during the presidential election campaign, when Mr Trump blasted the deal for its role in a decline in manufacturing jobs.

His stance is controversial within the US, with business groups and some top Republicans among the supporters of the deal.

The president's trade stance has also contributed to tension with America's closest neighbours.

Earlier this month, Canada filed a wide-ranging complaint with the World Trade Organisation that charged the US with violating international trade rules in its investigation of subsidies and other questions.

While Mr Lighthizer raised the complaint in his comments, Canadian Foreign Minister Chrystia Freeland said she views it as a separate issue tied to US tariffs on Canadian softwood lumber.

Canada hopes to negotiate a settlement on that question, she said.