With tensions and divisions mounting between some Republicans in Congress and President-elect Donald Trump over reported Russian interference in the 2016 election — Trump has questioned that involvement while some lawmakers in his party say the hackings were acts of war — U.S. intelligence experts were expected Thursday to testify on the controversy in the Capitol.

The testimony from intelligence officials was expected to contrast with Trump’s opinion of the situation, which coincides with statements from WikiLeaks founder Julian Assange. Assange is wanted by the United States for releasing troves of classified U.S. documents and his whistleblower website was responsible for the publication of hacked emails from the Democratic National Committee and the 2016 Democratic nominee’s staff. He has claimed that the Russian government did not provide his website with those election-year leaks.

A live stream of the testimony was scheduled to be available online here at 9:30 a.m. EST. Lawmakers were expected to answer questions from reporters after a briefing from intelligence officials before the public testimony, which can be watched here.

Three U.S.  officials told Reuters in a report published Thursday morning that American intelligence agencies obtained conclusive evidence only after the election that Russia had controlled the release of the election emails to WikiLeaks. The agencies had determined beforehand that Russian sources had hacked the email accounts but weren’t certain until after the fact that the WikiLeaks angle could be proved.

Trump has repeatedly questioned U.S. intelligence on the issue but has so far not received a briefing from U.S. officials. Members of the intelligence community noted in a Thursday NBC report that the Trump transition team and intelligence officials had become so estranged that even agreeing upon a date and time for such a briefing had become difficult. Instead, Trump has seemed to relied on statements from Assange, who said that a 14-year-old could have hacked the email accounts that his website later released. Assange, Trump pointed out in a Wednesday tweet, has denied getting the information from Russian sources.