US Republican presidential candidate Donald Trump says Hillary Clinton is not qualified to be president, agreeing with Bernie Sanders who thinks the Democratic frontrunner lacks what it takes to run the country.

The GOP presidential frontrunner tweeted on Saturday that he agreed with Sanders calling Clinton “unqualified.”

“Bernie Sanders says that Hillary Clinton is unqualified to be president. Based on her decision making ability, I can go along with that!” the billionaire businessman wrote.

Democratic presidential hopeful Sanders on Wednesday censured Clinton for her support of the invasion of Iraq in 2003, and said that she should apologize to the victims of the Iraq war, which she voted in favor of as a senator.

He also raised the issue of Hillary Clinton being unqualified to run the White House, citing “tens of millions of dollars” she is receiving from special interest groups through her super PAC.

The independent senator from Vermont defended the remark on Thursday, insisting he was fighting back after Clinton called him unqualified.

He softened his tone on Friday, saying his remarks that the Democratic frontrunner is “unqualified” for the job was a response to her recent attacks against him.

He did not back away from his earlier remarks, but did instead concede that Clinton is “extremely intelligent.”

Sanders also seemed to abandon his call for Clinton to apologize to the victims of the Iraq war.

Meanwhile on Friday, Sanders said Trump or Ted Cruz won the White House it would be an “unmitigated disaster” for the country.

“I think the idea of a Donald Trump or a Ted Cruz presidency would be an unmitigated disaster for this country,” Sanders said.

Trump, who has never held elected office, is leading the Republican race despite the fact that his campaign has been marked by controversial statements, including disparaging remarks about women, Mexican immigrants and Muslims.