KENTFIELD, California/BEIJING, June 21 (Reuters) – China hit back on Wednesday after U.S. President Joe Biden referred to President Xi Jinping as a “dictator”, saying the remarks were absurd and a provocation in an unexpected row following efforts by both sides to lower tensions.

Biden made his comments just a day after U.S. Secretary of State Antony Blinken visited Beijing to stabilize relations that China says are at their lowest point since formal ties were established.

Attending a fundraiser in California, Biden said Xi was very embarrassed when a suspected Chinese spy balloon was blown off course over U.S. airspace early this year. Blinken had said on Monday the chapter should be closed.

“The reason why Xi Jinping got very upset in terms of when I shot that balloon down with two box cars full of spy equipment in it was he didn’t know it was there,” Biden said.

“That’s a great embarrassment for dictators. When they didn’t know what happened. That wasn’t supposed to be going where it was. It was blown off course,” Biden said.

Xi became China’s most powerful leader since Mao Zedong after securing a precedent-breaking third term as president in March and head of the Communist Party in October.

He presides over a one-party system that many human rights groups, Western leaders and academics call a dictatorship because it lacks an independent judiciary, free media, or universal suffrage for national office.

Critics of Xi and his party are censored online and risk detention off line.

Biden also said China “has real economic difficulties”.

A Chinese foreign ministry spokesperson said Biden’s remarks were “extremely absurd” and “irresponsible”.

Expressing China’s strong dissatisfaction, foreign ministry spokesperson Mao Ning said Biden’s comments seriously violated facts, diplomatic protocol and China’s political dignity.

“They’re an open political provocation,” she told a news conference.

Asked how aware Xi had been about the balloon’s movements, Mao reiterated China’s previous explanation that the passage of the balloon through U.S. airspace had been unintended and caused by circumstances beyond its control.