By Brendan O'Brien
March 4 (Reuters) - U.S. President Donald Trump on Saturday accused former president Barack Obama of wire tapping him in October during the late stages of the presidential election campaign, but offered no evidence to support the allegation.
"How low has President Obama gone to tapp my phones during the very sacred election process. This is Nixon/Watergate. Bad (or sick) guy!," Trump said in a series of Tweets on his Twitter account early on Saturday.
In one of the tweets, Trump said the alleged wire tapping took place in his Trump Tower, but there was "nothing found".
Trump's administration has come under pressure from FBI and congressional investigations into contacts between some members of his campaign team and Russian officials during his campaign.
Obama imposed sanctions on Russia and ordered Russian diplomats to leave the U.S. in December over the country's involvement in hacking political groups in the Nov. 8 U.S. presidential election.
Trump's national security adviser, Michael Flynn, resigned in February after revelations that he had discussed U.S. sanctions on Russia with the Russian ambassador to the United States before Trump took office.
Flynn had promised Vice President Mike Pence he had not discussed U.S. sanctions with the Russians, but transcripts of intercepted communications, described by U.S. officials, showed that the subject had come up in conversations between him and the Russian ambassador.
Trump has often used his Twitter account to attack rivals and for years led a campaign alleging that Obama was not born in the U.S. He later retracted the allegation.
(Reporting by Brendan O'Brien in Milwaukee; Editing by Alexander Smith)