Questions continue to swirl in the wake of the allegations, reported first by The Washington Post on Monday afternoon.
Here is a roundup of the facts that have emerged.
What we know
The Post reported that the nature of the information was related to an Islamic State terrorist threat and was gathered by a United States intelligence partner. Russia is not a partner in the intelligence-sharing arrangement from which the information originated.
The White House released a statement shortly after the report was published, calling the story "false."
"I was in the room. It didn't happen," he added.
A senior U.S. official told ABC News that White House officials placed calls to the CIA and the National Security Agency to alert them that Trump shared information with the Russians. The official said that the calls were intended to make sure there was no misunderstanding about what he said.
The official also said that the meeting's notes were edited to remove sensitive information and that such redactions are routine.
Trump suggested in two Twitter posts this morning that he had the authority to divulge information to his Russian guests.
Speaking to reporters off-camera this afternoon, White House press secretary Sean Spicer said Trump’s meeting was "a discussion about a shared aviation threat."
"They shared and discussed a shared threat that our two countries have," he said.
During a press briefing today, McMaster said Trump "wasn't even aware where this information came from. He wasn't briefed on the source or method of the information [collection] either."
What we still don't know
The biggest questions that remain concern what exactly Trump said during the interaction and details about the intelligence that was disclosed.
Moreover, McMaster said that Trump made his decision based on the nature of the conversation. If there was no prior discussion about the disclosure, a typical interagency approval procedure may not have been followed.
"He made the decision in the context of the conversation, which was wholly appropriate," McMaster said of Trump.
"If the president wants to share intelligence with a country like Russia and ultimately if the original source of the intelligence is a foreign country, whoever is coordinating with the country — whether it's the CIA or the NSA — they go back and get permission from that country. The second part of the process is our intelligence officials will take a subset of the information that was originally provided so they can convey the threat and not disclose sources and methods and other sensitive information," Cohen said.
According to the Post, "The partner had not given the United States permission to share the material with Russia," suggesting the process Cohen described was ignored or retroactively followed.
"It creates the risk that the original provider of the information will be less inclined to share sensitive intelligence in the future," Cohen said. "That, I am sure, is what has intelligence officials concerned."
Some other key questions that need to be answered concern which country or agency provided the intelligence to the U.S., whether the conversation between Trump and the Russian officials was recorded and why he decided to share the information with them.
ABC News' Jonathan Karl and Cecilia Vega contributed to this report.