Washington (CNN) President Donald Trump on Monday announced the US would expand its existing sanctions against Venezuela with an executive order banning Americans doing business with President Nicolas Maduro's government.

The executive order freezes assets of the government of Venezuela and associated entities and prohibits economic transactions with it, unless specifically exempted. Exemptions include official business of the federal government and transactions related to the provision of humanitarian aid.

It marks an escalation from the already expansive US measures against the Venezuelan government since the start of the country's chaotic political and economic crisis earlier this year.

In a letter to Congress outlining the action Monday night, Trump said, "I have determined that it is necessary to block the property of the Government of Venezuela in light of the continued usurpation of power by the illegitimate Nicolas Maduro regime, as well as the regime's human rights abuses, arbitrary arrest and detention of Venezuelan citizens, curtailment of free press, and ongoing attempts to undermine Interim President Juan Guaido of Venezuela and the democratically-elected Venezuelan National Assembly."

Venezuela's political turmoil stems from presidential elections last year wherein Maduro secured another six-year term in a process widely viewed as a sham. Opposition leader Juan Guaido declared himself acting president earlier this year.