For decades it was one of Washington's closest alliances.

United in their fight against drug trafficking, Colombia and the United States co-operated closely, with the latter receiving hundreds of millions of dollars in US military assistance annually.

But now that alliance appears to be more fragile than ever.

The leaders of the two countries may have a similar style - forceful and not prone to mincing their words - but left-wing Gustavo Petro and Donald Trump come from opposing ends of the political spectrum and have clashed frequently since Trump returned to the White House in January.

On Sunday, tensions reached their highest point when Trump accused Petro of encouraging drug production in Colombia and announced the suspension of payments and subsidies to the South American country.

This came after Petro had in turn accused US officials of murdering a Colombian citizen and violating his country's sovereignty in one of the multiple strikes that the US military has carried out against alleged drug vessels in the Caribbean since early September.

BBC Mundo spoke to experts who warned that with the alliance in jeopardy, both Colombia and the US could be at risk of losing out while organized crime groups look set to benefit.

Colombia became one of the main beneficiaries of US aid in the early 2000s, receiving significant funding through initiatives aimed at combating drug trafficking. While this support has helped reduce the influence of guerrilla groups, questions remain about its long-term effectiveness.

The current military actions taken by the US may illustrate an escalation in response to drug-related issues, challenging the historical cooperation between these two countries. Moreover, the cuts in military and economic aid mark a drastic turn in foreign policy at a time when both nations may need each other the most.

As both leaders navigate an increasingly tense landscape, the implications for both countries are significant, with experts warning that the real winners may be the very drug trafficking networks they seek to dismantle.