It has been reported that National Security Advisor Michael Flynn discussed US sanctions against Russia with Russian Ambassador Sergey Kislyak in the month before Trump was sworn into office as president.

On Wednesday Flynn flatly denied that he discussed sanctions with Kislyak, but on Thursday be backed off his statement saying they spoke of many subjects and he could not remember. Meanwhile, the FBI is continuing to look into Flynn’s discussions with Kislyak.

Vice President Mike Pence has also made contradictory statements regarding the issue. About a month ago, Pence told CBS News in an interview that no discussion about the US expelling diplomats or other sanctions were ever raised. Those discussions included text messages, phone calls and in-person meetings.

Pence further said that no contact between members of Trump’s team and Russia had been made during the campaign, but Pence has also acknowledged that a handful of text messages and calls were exchanged with Kislyak. First, no one had talked to the Russians, and then he said some contact was made.

Nevertheless, speaking on condition of anonymity, nine current and former senior officials in several government agencies have all said Flynn’s reference to sanctions were explicit.

Two of those officials, the Washington Post reports, said “Flynn urged Russia not to overreact to the penalties being imposed by President Barack Obama, making it clear that the two sides would be in position to review the matter after Trump was sworn in as president.”

Officials in the Obama Administration had discussed whether Flynn had violated the law by interfering with US disputes with foreign governments. The law, which Flynn may have violated, has never been tested in the courts, the Logan Act of 1799, so it may be difficult to build a case against him.

Flynn said he has spoken to Kislyak on a range of subjects, but denied speaking to him about sanctions. Flynn said he didn’t recall what subjects were discussed. Kislyak has declined to answer questions regarding subjects he discussed with Flynn. The investigation is ongoing.