CÚCUTA, Colombia — Secretary of State Mike Pompeo had a lot to feel good about during his four-country swing through South America this past week.

During his visit to Santiago, Chile’s foreign minister stressed the importance of Washington’s “diplomatic pressure” in working to unseat Venezuelan President Nicolás Maduro.

In Peru and Paraguay, diplomats underscored their lockstep support for the U.S. goal of bringing relief to the millions of Venezuelan refugees flooding into neighboring countries.

And in Colombia, Venezuelans who have fled there thanked him for his efforts in the border town of Cúcuta, where the United States has positioned tons of aid in the event Maduro’s regime allows food and medicine into the country.

But as Maduro maintains his grip on the military and the pace of nations recognizing opposition figure Juan Guaidó as the rightful leader slows, Pompeo has more forcefully defended U.S. leadership in the crisis and the righteousness of its intent.

During a news conference in Lima, Pompeo responded testily when a Washington Post reporter asked whether Peru might consider engaging with Maduro if Western sanctions against the regime worsen the humanitarian and refugee crisis.

“Your question showed an incredible lack of understanding,” Pompeo said, following his Peruvian counterpart’s response. “To have suggested that somehow the policies that Peru has taken or that the Lima Group has taken or that the United States has taken have driven these refugees. You shouldn’t ask questions like that.”

When the reporter reiterated the intent of the question, Pompeo responded: “The responsibility for these refugees lies squarely with Nicolás Maduro, not any policies that any democratic nation has taken with our deep intent to make lives better for the Venezuelan people. A hundred percent of the refugee challenge that is faced by Peru and Colombia is the direct result of the Russians, the Cubans and Nicolás Maduro.”

Sanctions experts said questions about the impact of U.S. sanctions on the humanitarian situation remain important and shouldn’t be dismissed out of hand.

“As a sanctions analyst who is broadly supportive of sanctions pressure on Maduro, asking about humanitarian consequences is not only legitimate, but key to trying to calculate if our strategy is fulfilling our goals,” said Neil Bhatiya, a scholar at the Center for a New American Security, a bipartisan think tank in Washington.

“The goal of U.S. sanctions is to deprive the Venezuelan regime of revenue through oil sales, gold trading and other more illicit activities,” he said. “As that revenue declines, it is axiomatic that the regime will not have the resources to keep the Venezuelan economy afloat.”

Despite the uncertainty about Maduro’s future, the United States still has broad support in South America for its efforts to pressure him to step down nearly three months after saying he must go.

Maduro’s mismanagement of the economy, election fraud and clampdown on dissent have provoked widespread criticism, a point reiterated by Latin American leaders on Pompeo’s trip.

“We have said always with dictators, with tyrants, we do not dialogue,” Paraguayan Foreign Minister Luis Castiglioni said during Pompeo’s visit to Asuncion on Saturday. “Tyrants and dictators are combated, are fought against.”

As Maduro continues to hang on to power, U.S. officials have sought to expose what they consider the hypocrisies of his regime, including its blockage of aid in Colombia.

In the hot and muggy weather on Sunday, Pompeo toured the Simon Bolivar bridge connecting Venezuela and Colombia. Venezuelan forces in blue camouflage stood atop the bridge with riot gear, surrounded by lush tropical flora. Behind them, Venezuelan fuel tankers blocked the way.

Summoning the memory of Ronald Reagan, Pompeo said near a warehouse filled with aid: “Mr. Maduro, open these bridges. Open these borders. You can end this today.”