Beijing has apologised to Costa Rica for a balloon that flew over its territory, the Central American country's government said on Monday.

According to a brief statement from Costa Rica's foreign ministry, Beijing recognised that one of its balloons flew over Costa Rica, and its embassy in San Jose "apologised for the incident," while insisting the balloon was focused on scientific research, mainly weather studies.

Costa Rican officials were told by Beijing officials the balloon flight path deviated from its original plan and it had a limited ability to correct the error, according to the statement.

A Foreign Ministry spokesperson told reporters at a news conference in Beijing on Monday that the balloon spotted in Latin America was used for civilian purposes.

On Sunday, the head of Costa Rica's civil aviation agency said local officials had received reports of a balloon flying over the country last Thursday, after Colombia's military issued a statement on Saturday saying it had sighted an object similar to a balloon over its territory a day earlier.

Planes were notified at the time, but no further action was taken, according to the civil aviation director.

A US military jet shot down another balloon just off its Atlantic coast on Saturday, after days of frenzied speculation in the country over its mission.

And on Monday, US President Joe Biden asserted that Sino-US relations were not weakened by the episode. (Reuters)