KINGSTOWN, St. Vincent — The leaders of Guyana and Venezuela promised in a tense meeting Thursday that neither side would use threats or force against the other, but failed to reach agreement on how to address a bitter dispute over a vast border region rich with oil and minerals that has concerned many in the region.

Instead, a joint commission composed of the foreign ministers of both countries and other officials will address the problem, with a report expected within three months.

Guyanese President Irfaan Ali and Venezuelan President Nicolás Maduro agreed to meet again in Brazil within three months or at another agreed-upon time, according to an 11-point declaration read at a press briefing late Thursday at which no questions were allowed.

They also agreed to “refrain, whether by words or deeds, from escalating any conflict,” the declaration said.

Tension over the border region of Essequibo has raised worries about a military conflict, though many believe that is unlikely. Venezuela insists Essequibo was part of its territory during the Spanish colonial period and argues a 1966 Geneva agreement among Venezuela, Britain and then-British Guiana, now Guyana, nullified a border drawn in 1899 by international arbitrators.

The century-old dispute was recently reignited with the discovery of oil in Guyana. The dispute escalated when Venezuela reported that its citizens had voted in a Dec. 3 referendum to claim two-thirds of their smaller neighbor.

The hourslong meeting between the two leaders took place at the main international airport in the eastern Caribbean island of St. Vincent, with various Caribbean prime ministers attending.

The declaration noted the impasse between Ali and Maduro. It said Guyana believes the border controversy should be resolved by the International Court of Justice in the Netherlands, and that Venezuela did not consent to that and does not recognize the court or its jurisdiction in the dispute.

Neither Ali nor Maduro spoke to journalists after their meeting.

Earlier in the day, Guyana’s government issued a statement saying that Essequibo “is not up for discussion, negotiation or deliberation.” Ali echoed those comments during a news conference he held during a break in his talks with Maduro.

“All of this belongs to Guyana,” Ali said, pointing to a thick leather bracelet on his right wrist featuring the outline of Guyana. “No narrative propaganda (or) decree can change this. This is Guyana.”

Ali noted that while both parties are committed to keeping peace in the region, Guyana “is not the aggressor.”

Read Related Also: Prince Harry wins partial victory in newspaper phone hacking claim

“Guyana is not seeking war, but Guyana reserves the right to work with all of our partners to ensure the defense of our country,” he said.

Maduro said ahead of the meeting that “we will make the most of it so that our Latin America and the Caribbean remains a zone of peace.”

The two presidents clasped hands before their talks as leaders around them clapped.

White House National Security Council spokesperson John Kirby said that Biden administration officials were closely monitoring the rising tensions. “We don’t want to see this come to blows,” Kirby said. “There’s no reason for it to, and our diplomats are engaged in real time.”

Ali and Maduro first met individually with prime ministers and other officials from the region who had pushed for the meeting to try and defuse the situation.

Ahead of the meeting, Ralph Gonsalves, prime minister of St. Vincent and the Grenadines, said that “to use a cricket metaphor, this is not a one-day cricket match.”

“The fact that they will be talking is very important on friendly, neutral grounds like St. Vincent and the Grenadines,” he said.

Venezuela’s president has ordered state-owned companies to explore and exploit the oil, gas and mines in Essequibo. Both sides have put their militaries on alert.

Ali rejected in a letter to Gonsalves on Tuesday what he said was Maduro’s description of the “meddling of the United States Southern Command, which has begun operations in the disputed territory.”

The U.S. Southern Command has conducted flight operations within Guyana in recent days.

“Any allegation that a military operation aimed at Venezuela exists in any part of Guyanese territory is false, misleading and provocative,” Ali said in the letter.