The US National Security Advisor has denied reports that President Donald Trump revealed highly classified intelligence to the Russian Foreign Minister.
The Washington Post reported US President Donald Trump had disclosed highly classified information to the Russian foreign minister last week, potentially jeopardizing a source.
Mr Trump met Russian Foreign Minister Sergei Lavrov and Ambassador Sergey Kislyak in the Oval Office last week.
The newspaper, citing current and former US officials, said Mr Trump went off script and discussed details about an Islamic State terrorist threat related to the use of laptop computers on aircraft.
The information had been provided by a US partner through a highly sensitive intelligence-sharing arrangement, the Post reported.
The partner had not given Washington permission to share the material with Moscow, and Trump's decision to do so risked cooperation from an ally that has access to the inner workings of the Islamic State militant group, it said.
It is considered so sensitive it has not been shared with US allies.
Mr Trump's meeting with Lavrov and Kislyak at the White House came a day after he fired FBI Director James Comey, who was leading the agency's investigation into possible links between the president's election campaign and Moscow.
However, US National Security Advisor H R McMaster said he was in the room at the time of the meeting and nothing classified was discussed.
"The story that came out tonight as reported is false," he said.
"The President and the Foreign Minister reviewed a range of common threats to our two countries including threats to civil aviation.
"At no time were intelligence sources or methods discussed."
US officials told Reuters that US agencies were in the process of drawing up plans to expand a ban on passengers carrying laptop computers onto US-bound flights from several countries.
That was because of new intelligence about how militant groups were refining techniques for installing bombs in laptops, the officials said.
Assessments of the increased threat were so serious the Trump administration was considering also banning passengers from several European countries, including Britain, from carrying laptops in a cabin on US-bound flights, the officials said.
The United States has consulted about the intelligence with allied governments and airlines.