The US has placed sanctions on Colombia's left-wing president, Gustavo Petro, accusing him of failing to curb drug trafficking.

President Petro has allowed drug cartels to flourish and refused to stop this activity, US Treasury Secretary Scott Bessent said in a statement.

Sanctions have also been imposed on Colombia's Interior Minister Armando Benedetti, as well as Petro's wife and eldest son. They include barring them from accessing assets and properties they may have in the US.

Colombia was once a close ally of Washington's war on drugs, receiving hundreds of millions of dollars annually in military assistance. But Petro and Trump have clashed frequently since Trump's return to power.

Bessent stated that since Petro, a former guerrilla, came to power, cocaine production in Colombia has exploded to the highest rate in decades, flooding the United States and poisoning Americans. He added that Trump was taking strong action and would not tolerate drug trafficking into the US.

The Treasury said Colombia was the world's top exporter of cocaine, which it describes as posing a significant drug threat to the US.

In a separate statement, the state department mentioned that it would not certify Colombia's counter-narcotics efforts.

Petro denied the accusations, stating he had been fighting drug trafficking for decades and had helped the US reduce cocaine consumption. He called it a complete paradox - but not one step back, and never on our knees.

In recent weeks, the US military has ramped up operations in the southern Caribbean, striking vessels suspected of carrying drugs. Last week, Trump announced the suspension of payments and subsidies to Colombia.

This escalation in tensions follows Petro's condemnation of airstrikes on alleged drug vessels in the Caribbean as an act of tyranny, while accusing US officials of killing a Colombian citizen and violating national sovereignty.

Imposing sanctions on a head of state is rare but not unprecedented. Past targets of such actions have included leaders of countries like Russia, North Korea, and Venezuela.