United States President Donald Trump on Saturday accused Barack Obama of “wire tapping” his offices in the run up to the presidential elections. He likened the alleged spying to the Watergate scandal, however, he did not provide any proof to back his claim.

“Terrible! Just found out that Obama had my ‘wires tapped’ in Trump Tower just before the victory,” Trump said in a series of tweets. “Nothing found. This is McCarthyism! This is Nixon/Watergate. Bad [or sick] guy!” Without disclosing the source of his information, Trump said a “good lawyer” could make a case out of the “fact”.

He continued his tirade against Obama as he said that the Russian ambassador who met Jeff Sessions had allegedly visited the White House 22 times, and 4 times last year alone, during the former president’s rule. “The first meeting Jeff Sessions had with the Russian ambassador was set up by the Obama administration under education program for 100 ambassadors,” he wrote.

On Thursday, Sessions recused himself from all investigations related to Russian involvement in the 2016 presidential elections. His decision came a day after the Washington Post reported that Sessions, who was Trump’s campaign aide, had held meetings with Russian Ambassador Sergei Kislyak twice in 2016.

Sessions, who was the US Senator at that time, had received Russian Ambassador Sergei Kislyak in his senate office in September 2016. In another instance, he had a meeting with Kislyak at a Heritage Foundation event in July 2016 during the Republican National Convetion. However, Sessions maintained that he had met the Russian ambassador in his capacity as the US senator and not as Trump’s campaign aide, reported Reuters.