Leftist leader Gustavo Petro said he would sign a "letter of intent" to join the pact when he meets his Chinese counterpart Xi Jinping face-to-face in the coming days.

The Belt and Road Initiative is a central pillar of Xi's bid to expand his country's economic and political clout overseas.

For more than a decade it has provided investment for infrastructure and other large-scale projects around the world, offering Beijing political and economic leverage in return.

Until now Colombia has been one of the United States' closest and most steadfast trade and security partners in Latin America.

But the arrival of Colombia's first leftist president and the tariff-pocked second term of US President Donald Trump have put the relationship on ice.

The two leaders have sparred openly on social media over deportations and traded tit-for-tat tariff threats.

On January 26, Petro denied entry to two US military planes carrying hundreds of deported Colombians.

A furious Trump responded by imposing tariffs of 25 percent on Colombian products, to which Bogota replied in kind before backing down and sending its own planes to bring home the migrants.

Petro has since spoken about the need to steer Colombia's trade towards China, but Tuesday's announcement is the first major move in that direction.

Chinese officials in Bogota have been pressing Petro's government to join the pact before he leaves office next year.

Petro indicated that the letter of intent would not be binding: "Future governments will decide if this intention becomes a reality."

But Colombia's signature will come as major boost to Beijing in its battle for influence with the United States.

It comes just months after Panama announced its withdrawal from the initiative, after fierce US pressure.

Colombian business groups expressed shock at Petro's move.

"Does Colombia want to do this right now? In exchange for what?" asked Bruce Mac Master, president of the National Association of Colombian Businesspeople.

"What justification is there from the point of view of today's international strategy? How does it affect the relationship with our trade allies who buy most of our exports?"

The United States is Colombia's largest trading partner, but imports from China recently outpaced those from the United States.

Javier Diaz, president of the National Association of Foreign Trade, described Petro's decision as "inconvenient".

The date of Petro's visit to China has not yet been announced officially.