After pleading not guilty to 34 felony counts in a New York court, former United States President Donald Trump has slammed the Joe Biden administration, saying "our country is going to hell".

Trump also criticised the current justice system of the United States, calling it "lawless". The former US President also said Biden and Hunter Biden must be investigated, urging the Republican party to go against the father-son duo.

"I never thought anything like this could happen in America -- never thought it could happen. The only crime that I've committed is to fearlessly defend our nation from those who seek to destroy it," he was quoted as saying.

Meanwhile, Manhattan District Attorney Alvin Bragg vowed he will not allow Trump to get away with lawbreaking after charging him with a string of felonies over alleged hush money payments, reports AFP.