Former South Carolina Governor Nikki Haley accused Republican rival Donald Trump of being "obsessed" with dictators and too old to lead on Saturday in a final stretch of campaigning in New Hampshire ahead of Tuesday's presidential nominating contest.

The former U.S. president ramped up his verbal attacks and targeted Haley's Indian heritage as the former ambassador to the United Nations sought to blunt Trump's momentum following his victory last Monday in the Iowa caucuses.

New Hampshire boasts a more moderate brand of Republicanism with a semi-open primary that can attract more centrist voters, who may be turned off by Trump's four criminal cases, authoritarian language and efforts to overturn his 2020 re-election loss.

Haley spoke to reporters following an event in Peterborough, New Hampshire, and emphasized Trump’s relationships with strongmen such as Russia’s Vladimir Putin, Chinese President Xi Jinping and North Korea’s Kim Jong Un.

Her campaign released a TV ad that will run in New Hampshire featuring the mother of Otto Warmbier, who died in 2017 after being held in North Korean custody. Haley accused Trump of writing “love letters” to Kim after Warmbier was recovered. “He is obsessed with these dictators,” she said.

Haley's increasingly vocal criticism of Trump is a shift for a candidate who has shied away from sharp attacks on her former boss even as she has sought to sideline him, so far unsuccessfully, in the Republican race.