BEIJING, June 21 (AFP) - China's foreign ministry on Wednesday (Jun 21) slammed comments by US President Joe Biden equating Chinese leader Xi Jinping with "dictators" as an "open political provocation".

Speaking at a fundraiser in California on Tuesday, Biden said Xi had been angered over an incident in February when a Chinese balloon - which Washington says was used for spying - flew over the United States before being shot down by American military jets.

His comments come just days after US Secretary of State Antony Blinken concluded a visit to Beijing aimed at re-establishing lines of communication in order to avoid conflict between the two global powers.

"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 is he didn't know it was there," Biden said.

"I'm serious. That was the great embarrassment for dictators, when they didn't know what happened."

Beijing's foreign ministry termed Biden's comments as "ridiculous".

"The relevant remarks by the US side are extremely ridiculous and irresponsible, they seriously violate basic facts, diplomatic protocol and China's political dignity," foreign ministry spokeswoman Mao Ning said at a Wednesday briefing.

"China is strongly dissatisfied with and firmly opposed to this," she added.

The White House tried to ease tensions later on Wednesday, saying Blinken "made some progress" during his trip to China and that Washington still had "every expectation of building on that progress."

"Diplomacy, including that undertaken by Secretary Blinken, is the responsible way to manage tensions," a senior administration official said, adding "it should come as no surprise that the president speaks candidly about China and the differences that we have."