WASHINGTON • The White House is probing ongoing leaks of US President Donald Trump's private conversations with foreign leaders, including a report that he criticised a 2011 US-Russia nuclear arms treaty during last month's call with Russian President Vladimir Putin.

"We are looking into the situation, and it is very concerning," White House press secretary Sean Spicer said, deploring "the idea that you can't have a conversation without that information getting out... We are trying to conduct serious business on behalf of the country."

On the same day as the Putin call, on Jan 28, The Washington Post reported that Mr Trump told Australian Prime Minister Malcolm Turnbull their talk was "the worst call by far" and blasted him over a pending refugee deal negotiated by the Obama administration. Tensions were also reported during a call the day before with Mexican President Enrique Pena Nieto. Following the Australia and Mexico reports, Mr Trump told Fox News the leaks were "disgraceful" and accused "Obama people" still serving in the White House of being responsible.

During the Putin call, the Russian leader raised the possibility of talks on a number of issues, including the New Start treaty limiting nuclear weapons deployments, according to a report on Thursday by Reuters.

The news agency said Mr Trump paused to ask aides what the treaty was, and then denounced it as favouring Russia. Mr Spicer said Mr Trump had merely sought an opinion from an adviser during the conversation, which was conducted via a translator: "It wasn't like he didn't know what was being said."

Mr Jeffrey Lewis, an arms control expert at the Middlebury Institute of International Studies at Monterey, California, said the call was troubling because it showed Mr Trump has not taken the time to learn anything about nuclear policy since the election.

WASHINGTON POST