US President Donald Trump met with oil executives in Washington on Friday, as he pushed for major investments in Venezuela.

But no major financial commitments were immediately forthcoming from the meeting, with the head of ExxonMobil warning the South American country was currently un-investable.

Trump has said he expects big oil companies to direct at least $100 billion (£75 billion) toward the country, but industry analysts have warned many companies will be reluctant to go into a situation that still carries significant risk.

Last week the US seized Venezuelan leader Nicolás Maduro, who is now being held in jail in New York.

Maduro's second-in-command, vice president Delcy Rodríguez, who is seen as more of a pragmatist, is now interim president.

Executives of the biggest US oil majors who attended the meeting acknowledged that the country, which is sitting on vast proven oil reserves, represents a major opportunity.

But at a press conference with Trump they warned they would need to see significant changes inside Venezuela, as well as a welcome from the local government and its people, to make it an attractive place to put money.

We have had our assets seized there twice and so you can imagine to re-enter a third time would require some pretty significant changes from what we've historically seen and what is currently the state, Exxon's chief executive Darren Woods said. Today it's un-investable.

Venezuela has had a complicated relationship with international oil firms since oil was discovered in its territory more than 100 years ago.

Certainly, Chevron remains the last major American oil firm still operating in the country, while a handful of companies from other nations, including Spain's Repsol and Italy's Eni, were represented at the White House meeting.

Exxon and ConocoPhillips, which were also in attendance, have been fighting to recoup billions in dollars they say they are owed after the 2007 nationalisation of their assets.

Trump has alluded to the issue repeatedly this week to justify his intervention, including on Friday, but he downplayed the chances of recovery in the meeting, echoing comments by other administration officials in recent years who said repayment of those debts was not an immediate priority.

We're not going to go back, Trump said. He said his administration would work to strike a deal with companies to bring his vision for reviving the industry to reality.

However, while Venezuela's vast reserves offer potential, the actual production has suffered from decades of mismanagement and the impact of US sanctions which have limited access to global markets.

At roughly 1 million barrels per day, the country's production now accounts for less than 1% of global supply.

The White House has indicated it is considering a selective rollback of the restrictions on Venezuela, yet the intention to maintain control over oil sales to leverage pressure on the Venezuelan government remains a priority.

In the coming weeks, Chevron expects to bolster output, and Exxon is sending a technical team to evaluate the situation.

We are open for business, Trump declared.

While optimism persists among major companies about the potential for investment in Venezuela, analysts note that substantial increases in production will require significant effort and commitment under the right conditions.

Overall, while the ambitious $100 billion investment figure is seen as a beacon of hope for revitalizing Venezuela's oil sector, it will take time and concerted action to make such an investment actually feasible.