Donald Trump is the “shadiest, most corrupt” person to ever become US President, according to a prominent member of Barack Obama’s cabinet.
Julian Castro, the current Housing and Urban Development Secretary, slammed the President-elect in a series of tweets.
He warned the Republicans' majority in both the Senate and the House of Representatives means the businessman will be free to act unimpeded.
Mr Castro also appeared to suggest Mr Trump could be impeached - saying if the Democrats won control of one house of Congress the Republican would be "done".
He wrote: “So Trump-- the shadiest, most corrupt guy to take the Oval Office, will have no strong federal checks and balances. Has to change”.
“Trump is so corrupt that if Democrats controlled even one chamber of Congress, he'd be done before he even got started.”
Mr Castro ended both tweets with the hashtag #2018, a reference to the next congressional elections in which the Democrats hope to win back control of Congress to block Mr Trump’s policy agenda.
The President-elect has been accused of a series of offences in his business dealings. It has been alleged he used his charitable foundation to benefit his own family, defrauded “Trump University” students out of thousands of dollars and has links to the mafia. Mr Trump denies all the accusations.
Mr Castro has previously warned of the “real, meaningful and negative” consequences of Mr Trump’s election and said there would be “severe consequences”.
A lot of Americans now feel “like there’s a target on their back, that Donald Trump won’t be a President for everyone”, he said following the Republican’s victory.
Mr Castro called the President-elect a “bully” who “likes to pick on people who can’t fight back”.
The 42-year-old Obama ally, whose grandmother moved to the US from Mexico, was touted as a possible running mate for Hillary Clinton and has since been tipped as a potential Democratic presidential candidate in 2020.
Mr Castro’s claims come as Mr Trump continues to fill senior posts in his administration ahead of formally taking office on 20 January.
He confirmed earlier this week that Thomas Bossert, a former deputy homeland security adviser to President George W. Bush, will be his chief adviser on security and counter-terrorism issues.
Mr Castro will be succeeded at the Department for Housing and Urban Development by Ben Carson, the neurosurgeon who ran against Mr Trump for the Republican presidential nomination.
