WASHINGTON • Did Donald Trump make secret promises to Vladimir Putin?

What did the US President tell his Russian counterpart at their Helsinki summit?

US senators, distressed by the Republican billionaire's recent behaviour, were to demand answers from his Secretary of State Mike Pompeo yesterday, when he provides the most closely watched congressional testimony of his young tenure as the nation's top diplomat.

Lawmakers have been eager for Mr Pompeo to report back about a previous critical summit June 12 in Singapore between Mr Trump and North Korean leader Kim Jong Un.

Their demand became all the more urgent after Helsinki, in particular the joint press conference during which Mr Trump appeared to accept Mr Putin's denials rather than US intelligence conclusions that Russia had interfered in the 2016 presidential election.

"The Helsinki press conference was a sad day for our country, and everyone knows it," Senator Bob Corker, the Republican chairman of the Senate Foreign Relations Committee and an occasional Trump critic, told reporters on Tuesday.

Russia will therefore be the primary focus of Mr Pompeo's appearance before the committee.

But Mr Corker made it clear his panel will also grill Mr Pompeo about his recent trip to Pyongyang, Mr Trump's "undermining" of Nato and the defence alliance's principle of mutual defence, as well as the President's controversial trade tariffs which appear to be mushrooming into a trade war.

"I will testify about a lot of things including the relationship between the United States and Russia" and the "incredibly important" Trump-Putin summit, Mr Pompeo said.

The closed-door meeting was panned by US lawmakers and observers, but Mr Pompeo insisted it was "one I think the world will have benefited from when history is written".

AGENCE FRANCE-PRESSE