— In a meeting with regional leaders, Vice President Pence on Monday announced minor new U.S. sanctions against loyalists of President Nicolás Maduro and called on other nations to follow the Trump administration’s lead in freezing the assets of Venezuela’s state oil giant PDVSA — a move meant to further cut Maduro’s international cash flow.

Following a weekend in which the Venezuela military and pro-government militias violently thwarted an opposition attempt to break Maduro’s blockade of humanitarian aid, Pence arrived in Bogota to reiterate that Washington will not back away from diplomatic confrontation. His trip comes as some in the Venezuelan opposition have begun openly calling for the use of “force” to oust Maduro’s socialist government.

Pence did not publicly back immediate military force, but he reiterated a long-standing administration stance that all options were being considered.

“As we continue to bring economic and diplomatic pressure to bear on the Maduro regime, we hope for a peaceful transition to democracy, but as President Trump has made clear, all options are on the table,” he said in an address to a 14-nation diplomatic consortium called the Lima Group, which cannot compel Maduro to leave but is seen as the most influential body to back his opponent.

Pence later acknowledged to reporters that Venezuelan opposition leader Juan Guaidó has sought assurances that the United States could use force if necessary, but the vice president did not set a red line for that decision or hint at what he would recommend to Trump.

“I reassured him” that force remains an option, Pence said, “but we hope for better. We hope for a peaceful transition.”

Pence singled out Mexico, Uruguay and the eastern Caribbean nations for not recognizing Guaidó as the legitimate president.

“We believe there can be no bystanders,” he said, adding, “Our message today very much was intended to say to Mexico, to Uruguay to nations across eastern Caribbean that they need to come off the sidelines.”

Guaidó slipped over the Colombian border with his wife several days ago to meet with Pence and the other leaders. His defiance of a travel ban imposed by the Maduro-backed Supreme Court and his meeting with Pence appear to put him at further risk, and it is unclear how or when he will be able to return. His absence could serve to strengthen Maduro’s hand.

And in a move that underscored the probability that the 3 million Venezuelans who have fled their country’s chaos are unlikely to return home soon, the United States also will provide an additional $56 million in humanitarian aid. This latest tranche targets Venezuelans who have fled their homeland for Colombia and Brazil.

According to the State Department, the relief will provide shelter, food, medical services and support in earning a livelihood to sustain exiles while they are living in neighboring countries. That brings the total U.S. aid to Venezuelans in the past two years to $195 million, plus an additional $20 million for food and medical supplies that are stockpiled along the border in the event that they can ever be delivered.

“We got a long way to go,” Pence said. “I made it clear to President Guaidó we’re going to continue to press on. We’re going to continue to call allies to join with us. We’re going to continue to isolate the Maduro government economically and diplomatically until democracy is restored.”

Sen. Marco Rubio (R-Fla.), who has aggressively pushed for more pressure on Maduro, tweeted Monday that the international community must do more to punish Maduro and his allies. The senator urged seizing PDVSA’s assets and turning it over to the opposition government, denying visas to Maduro allies and their families, and tracking down their money to return it to the Venezuelan people.

When it comes to sanctions, however, the United States is running out of options, as Monday’s announcement showed. Last month, the Treasury Department imposed sweeping penalties that effectively cut off Maduro’s biggest source of hard currency — oil sales to the United States. Having done that, the United States has pulled the most powerful economic lever it had.

Sanctions risk worsening Venezuela’s humanitarian crisis, since the nearly bankrupt government — now even more cash-strapped — is the chief importer of food and medicines. The once-wealthy nation is already reeling from hyperinflation and international penalties, and some 3 million Venezuelans have fled the country.

The U.S. calculation is that the sanctions will make Maduro’s rule un­tenable. But there are still no guarantees they will do anything more than make a bad situation worse on the ground.

The Treasury Department said Monday that it is sanctioning four Venezuelan governors aligned with Maduro, a modest step, saying they are corrupt and had facilitated the blockade of humanitarian aid to the country over the weekend.

“The illegitimate Maduro regime’s attempts to blockade international aid intended for the Venezuelan people are shameful,” Treasury Secretary Steven Mnuchin said in a release. “Treasury is targeting four state governors aligned with former President Maduro for standing in the way of severely needed humanitarian assistance and prolonging the suffering of the Venezuelan people.

Sanctions were placed on two governors who head states on the border with Colombia.

Omar José Prieto Fernández is governor of Zulia, which the Treasury Department characterized as a hub for organized crime, drug trafficking and murder-for-hire. Prieto recently said he would declare independence if a transition government takes power in Venezuela.

Ramón Alonso Carrizalez Rengifo is the governor of Apure. The Treasury Department said he had “endorsed” threats of violence against opposition protesters.

Also sanctioned were Jorge Luis García Carneiro, the governor of Vargas, who has rejected Guaidó as interim president, and Rafael Alejandro Lacava Evangelista, the governor of Carabobo. The Treasury Department described Lacava as a Maduro intermediary involved in hiding overseas.

The cash flow into PDVSA — Venezuela’s state oil giant — is the single-largest generator of hard currency for Maduro’s government, and the United States, before Trump’s sanctions, was its biggest buyer. Should other countries freeze PDVSA accounts, as the United States had done and Pence called for Monday, it could further pressure Maduro, but may not be decisive.

“Lima Group countries are minor players in Venezuelan oil sales,” said David Smidle, Senior Fellow at the Washington Office for Latin America, a Washington-based think tank. “I don’t think it would have a huge financial impact, but it could have a symbolic effect. From the U.S. perspective, it would allow them to say the actions are multilateral.”

The Venezuelan opposition on Saturday mounted a massive operation seeking to haul in hundreds of tons of U.S. and other foreign aid from Colombia, Brazil and Caribbean islands — an effort that was repelled by Maduro’s military and gun-toting militias with tear gas, rubber bullets and live fire that opposition official say left 8 dead and hundreds wounded. Billed as a way to relieve a humanitarian crisis in a collapsing socialist state facing food and medical shortages, the plan was also designed to pressure Maduro’s military to betray him by disobeying orders to maintain the blockade.

More than 150 men and women from the rank and file did abandon their posts, denouncing Maduro and seeking refuge in Colombia. But the effort did not cause the massive military rupture with Maduro that the opposition had had hoped for, while some of the aid was burned on truck beds.

In a sign of the increasing tensions, senior opposition politician Julio Borges tweeted Sunday night that during the Lima Group, the opposition “will urge for an escalation of diplomatic pressure and the use of force against the dictatorship of Nicolás Maduro.”

In his address to the diplomatic gathering Monday, Guaidó was emotional and told the group in Spanish that he could not be understated in light of the weekend’s “massacre.”

Guaidó repeated a pledge to restore private property rights in Venezuela under an interim government that would take over from Maduro and hold new elections. He said a future democratic Venezuela would no longer tolerate terrorist groups that the United States accuses Maduro of encouraging.

The delegates, including Pence, stood for a long ovation when Guaidó was done.

Earlier Monday, Pence met with Guaidó and Latin American nations that support his challenge to Maduro.

Guaidó declared himself the rightful interim leader in January, and the United States was the first to recognize him.

“President Guaidó, we admire your courage,” Pence said as he posed for photographs with the young Venezuelan and Colombian President Iván Duque.

“I want to assure you, President Guaidó, the tragic events of this last weekend have only steeled the resolve of the United States,” Pence said.

Guaidó thanked Pence and Trump and vowed to continue trying to move humanitarian aid and oppose Maduro.

“The dilemma is not between war and peace — we all want peace,” he said through an interpreter. “Peace is not committing massacres against populations of indigenous people,” Guaidó said.

Later Monday, following the meeting of the Lima Group, Pence met with Venezuelan refugee families living here. Colombia has taken in more than 1 million refugees.

He embraced a sobbing elderly man who told him in Spanish how he and his family wanted to return home. The man and his family were among a small group of Venezuelan refugees gathered before a tableau of donated supplies marked “USAID” and noting, in Spanish, that the materials are a gift from the people of the United States.

Pence told the man in English, “We are with you.”

Guaidó had already wrapped the man in a long embrace as the man cried out and struggled for words.

After shaking hands, the refugees broke into an emotional rendition of the Venezuelan national anthem as Guaidó placed a hand to his heart and sang loudly.

Faiola reported from Caracas and Morello reported from Washington. Marina Lopes in Sao Paolo and John Wagner in Washington contributed to this report.