In an extraordinary breach of protocol, Donald Trump’s national security adviser Michael Flynn spoke to Russia’s U.S. ambassador about the lifting of sanctions before Trump took office.

Both Flynn and Vice President Mike Pence had repeatedly denied this claims in recent days, but a report published by the Washington Post late Thursday confirms the conversation did take place – with Flynn and Russian Ambassador Sergey Kislyak discussing the possibility that sanctions imposed by former President Barack Obama could be quickly reversed.

The claims are based on reports from nine current and former officials in the administration, who viewed Flynn’s conversations with Kislyak as “an inappropriate and potentially illegal signal to the Kremlin” that sanctions could be lifted.

White House backtracks

When asked Wednesday whether he had ever discussed sanctions with Kislyak on the phone, Flynn twice said no, but a day later he backtracked – with a White House spokesperson saying that “while [Flynn] had no recollection of discussing sanctions, he couldn’t be certain that the topic never came up.”

Just days before Donald Trump’s inauguration, Pence also denied that Flynn and Kislyak discussed sanctions. “They did not discuss anything having to do with the United States’ decision to expel diplomats or impose censure against Russia,” Pence told CBS News.

However, Pence has also backtracked, with a spokesman for the vp saying that he based his account on conversations he’d hadwith Flynn. One of the officials, speaking to the Post, said that “either Flynn had misled Pence or that Pence misspoke.”

Kremlin spokesman Dmitry Peskov has denied that there was any discussion of sanctions between Flynn and Kislyak, saying the information is “not correct.”

Flynn and Kislyak are said to have communicated via text message, phone call, and in person on numerous occasions, and while no explicit guarantee was given that sanctions would be lifted, the calls did leave the impression that it could well be a possibility.

Contrary to what Trump’s team has stated publicly, the calls allegedly began prior to the election last November and continued throughout the transition period.

As a result, some officials believe that Flynn may have broken the law, citing the Logan Act, which states that a U.S. citizen cannot interfere in foreign diplomacy. The act dates back to a 1799 statute that has never been used to convict anyone, leaving officials unsure as to what would be needed to secure a conviction.

Reports last month said that Flynn spoke to Kislyak on five separate occasions on Dec. 29 – the same day that Obama imposed sanctions on 35 Russian intelligence agents – with the calls said to have taken place after the Kremlin was informed of the sanctions but before Putin announced there would be no reprisals.

Obama imposed the latest set of sanctions against Russia for its alleged role in hacking into the DNC servers and disrupting the presidential election. Previously the U.S. had imposed sanctions on Russia for its annexation of Crimea in 2014.

On Wednesday, White House press secretary Sean Spicer said the two sets of sanctions would be treated differently. “Until Russia leaves Crimea, those sanctions are a non-starter,” but he failed to clarify whether or not the more recent sanctions could be lifted.

Last month the Washington Post reported that the FBI had picked up communications between Flynn and Kislyak but had not found any evidence of wrongdoing or “illicit ties to the Russian government.” However reports by the Wall Street Journal, CNN and CBS refute this account, suggesting the FBI is still investigating the communications.

Flynn’s links with Russia

Just last month, Democrats called for an investigation into whether Flynn had violated Pentagon policy by receiving payment for a speech he gave at a banquet celebrating the 10th anniversary of state-run television station RT — an event also attended by Putin.

As a retired army officer, Flynn is prohibited from accepting direct or indirect payment from a foreign government, but he has said the payment came through a speakers bureau. Flynn has appeared on RT several times since, where he has argued for closer ties between the two countries.