WASHINGTON -- US President Donald Trump has said his slogan for his second presidential bid would be "keep America great", building on his previous slogan "make America great again".

"Our new slogan when we start running in, can you believe it, two years from now, is going to be 'Keep America Great' exclamation point," Trump said Saturday evening at a Pennsylvania rally.

"We can't say 'Make America Great Again' because I already did that," Trump said as he boasted his accomplishments in the past year, including a massive tax cut, booming stock market and healthy job numbers.

Trump told the Washington Times in January his intention of coining the phrase and instructed his lawyers to trademark the slogan.

Trump has showed strong interest in his next presidential term, announcing his bid by naming his former campaign advisor Brad Parscale as his new campaign manager in late February, earlier than any former president.

The previous record was held by Barack Obama, who made his second campaign announcement 582 days before the general election date. Trump broke the news 980 days before election day, US media reported.

Trump is reportedly in good standing financially for his campaign, compared with his would-be competitors.