Colombian President Gustavo Petro is heading to Washington for a high-stakes trip to meet US President Donald Trump, the first in-person meeting between the two after months of escalating tensions and angry rhetoric.

Venezuela, drug trafficking, oil, security and US strikes on alleged drug vessels will be high on the agenda when they meet at the White House on Tuesday.

While the two men were cordial in a phone call after the 3 January US military operation to seize Venezuela's President Nicolás Maduro, Petro has since said he believes that there is a real threat of military action against Colombia.

Trump, for his part, has previously said that a military operation in Colombia sounds good.

Tuesday's meeting follows months of the two leaders trading barbs - with Petro repeatedly criticising the repeat US strikes on the alleged drugs boats in the Caribbean and Pacific, as well as the White House's immigration policies.

In an interview with the BBC last month, Petro went as far as to compare US Immigration and Customs Enforcement (ICE) agents to Nazi brigades and accused the US of treating other countries as part of its empire.

On the US side, Trump has accused Petro's government of not doing enough to stop the flow of cocaine heading north, and has vowed to expand strikes to land targets across the region.

But the acrimony seemed to dissipate following a cordial phone call between the two leaders, which a Colombian official later described as an 180-degree turn from both sides.

According to diplomatic sources, one man - Rand Paul, US Senator for Kentucky - was instrumental in setting up the conversation.

I believe in diplomacy and I thought our relations were going in the wrong way, the senator told the BBC. And I'd like to see our relations improve.

Ahead of Tuesday's visit, Colombian Foreign Minister Rosa Yolanda Villavicencio said that much of the conversation would focus on shared US and Colombian concerns over security in Venezuela, with which Colombia shares a 1,367 mile (2,200km) border.

Much of that border is under the sway of the National Liberation Army, or ELN. This Colombian guerrilla group, which was founded in the 1960s, controls drug trafficking, extortion, contraband and illegal mining of gold and coltan in border states such as Zulia, Táchira, Apure, and Amazonas - and works with corrupt elements of the Venezuelan government.

While in Colombia the group operates against the government, in Venezuela it often serves the interests of the state, according to security analysts, and operates as a paramilitary-style organisation.

Money made by the ELN's mineral and drug trafficking operations, she explained, often included payments to elements of the Venezuelan military.

Following the fall of Maduro, Petro has already ordered 30,000 Colombian soldiers to the Venezuelan border to prevent the group from crossing over.

But even with multiple areas in which the two can cooperate, there still exists the potential for an Oval Office clash of the sort that the presidents of Ukraine and South Africa both experienced with Trump last year.

Trump loves you one day, dislikes you the next day and reverts to loving you a couple days after, said Brett Bruen, a former diplomat who now runs the Global Situation Room, a Washington-based strategic communications firm.

Despite the tensions, cooperation has continued between the two nations' militaries, as well as between the US Drug Enforcement Administration (DEA) and Colombian police.

There is no fight against the cocaine trade without Colombia, said Jeremy McDermott, the co-director of Insight Crime. The threat to cut off Colombian intelligence to the US could also undermine all investigations.

Colombian officials have said that the visit will also serve as an opportunity to showcase their government's counter-narcotics efforts to a sceptical White House.

As both leaders prepare for this pivotal meeting, the outcome could significantly impact US-Colombia relations and the regional dynamics in South America.