Iran's foreign minister warned Tuesday that "acts of sabotage" and sanctions will give the United States no extra leverage in talks on reviving a troubled 2015 nuclear deal.

Nascent talks aimed at bringing the United States back into the 2015 nuclear deal with Iran broke Friday without any immediate signs of progress on the thorny issues dividing Washington and Tehran, but with delegates talking of a constructive atmosphere and resolving to continue the discussions.

Two working groups that have been meeting in Vienna since Tuesday to brainstorm ways to secure the lifting of American sanctions and Iran's return to compliance with the deal reported their initial progress to a joint commission of diplomats from the world powers that remain in the deal — France, Germany, Britain, China and Russia.

The United States and Iran will open indirect talks next week in Vienna as the European Union spearheads efforts to bring President Joe Biden's administration back into a nuclear accord.

The United States stood on the brink Sunday of recording 500,000 Covid-related deaths since the start of the pandemic, while nations globally pressed on with vaccination rollouts, including with Australia giving its first shots.

The United States on Friday warned China against the use of force in disputed waters as it reaffirmed its view that Beijing's assertive campaign in the South China Sea is illegal.

Canada's border with the United States will remain closed to all non-essential travelers until March 21, Public Safety Minister Bill Blair announced Friday.

Washington has urged the leaders of Myanmar's new military regime to refrain from violence and relinquish power, after the death of a young anti-coup protester sparked new anger against the junta.

Much of the country has been in uproar since troops deposed civilian leader Aung San Suu Kyi on February 1, with large street demonstrations in both urban centres and isolated villages.

Iran on Friday renewed its call for the US to lift all sanctions imposed by former president Donald Trump, after an offer for talks from new President Joe Biden's administration.

The United States said Thursday it was easing draconian restrictions imposed by Donald Trump's administration on movements of Iranian diplomats accredited at the United Nations, headquartered in New York City, as part of a bid to reduce tensions.

Turkey on Thursday rejected a US call to release jailed civil society leader Osman Kavala, accusing Washington of interference.