The former president of Costa Rica, Oscar Arias, says his US visa has been revoked.

Arias, a Nobel laureate, said he was informed of the decision weeks after he had publicly criticised Donald Trump, comparing the behaviour of the US president to that of a Roman emperor.

The 84-year-old, who was awarded the Nobel Peace Prize for his role in brokering an end to conflicts in Central America, said US authorities had given no explanation.

Arias hinted, however, that it may be due to his rapprochement with China during the time he was president from 2006 to 2010.

Speaking at a news conference in the Costa Rican capital, San José, Arias said he had "no idea" what the reason for the cancellation was.

He said he had received a "terse" email "of a few lines" from the US government informing him of the decision.

He added that he thought that it was not President Trump but the US State Department which had taken the decision.

While he said it would be conjecture on his part to speculate about the reason behind the visa revocation, he did point out that "I established diplomatic relations with China.

"That, of course, is known throughout the world," he told journalists of his 2007 decision to cut ties with Taiwan and establish them with China instead.

The Trump administration has sought to oppose China's influence in the Western hemisphere and has accused a number of Central American governments of cosying up to the Chinese government and Chinese companies.

However, it has been supportive of the current Costa Rican President, Rodrigo Chaves, praising his decision to exclude Chinese firms from participating in the development of 5G in Costa Rica.

But this perceived closeness between President Chaves and the US was criticised by Arias, who wrote a post on social media in February saying that "it has never been easy for a small country to disagree with the US government, less so when its president behaves like a Roman emperor, telling the rest of the world what to do".

He added that "during my governments, Costa Rica never received orders from Washington as if we were a banana republic".

Arias is not the only Costa Rican to have had his US visa revoked. Three members of the country's national assembly who opposed President Chaves's decree to exclude Chinese companies from participating in the development of 5G have also had theirs cancelled.