Pope Francis has said he fears bloodshed in Venezuela as the South American country braces for a week of fresh protests against its embattled president, Nicolás Maduro.

Speaking on the papal plane as he returned from a five-day visit to Panama, Pope Francis told reporters: “In this moment, I support all the Venezuelan people because they are a people who are suffering.

“I suffer for what is happening in Venezuela,” he added. “What is it that scares me? Bloodshed.”

Pope Francis declined to publicly side with either Juan Guaidó, the opposition leader who last week declared himself Venezuela’s rightful interim president, or Maduro, who has governed since being elected in the wake of Hugo Chávez’s 2013 death.

Russia and China have backed the latter while the US, Canada and more than a dozen Latin American countries say they support Guaidó. EU countries including Britain, France, Germany and Spain on Saturday gave Maduro – who they say was fraudulently re-elected last May – an eight-day ultimatum to hold fresh election or they too would recognize Guaidó.

“If I said, ‘listen to these countries’ or ‘listen to those countries’ I would put myself in a role that I do not know, it would be a pastoral imprudence on my part and I would cause damage,” Pope Francis said.

Pope Francis answers questions after leaving Panama City on 27 January. Photograph: Alessandra Tarantino/AFP/Getty Images

At a mass in Panama City attended by an estimated 700,000 on Sunday Pope Francis said he “asked the Lord to seek and find a just and peaceful solution to overcome the crisis that respects human rights and exclusively seeks the good of all people”.

Pope Francis is not alone in fearing violence in the oil-rich but economically devastated South American nation.

“I am worried about a country that can fragment under different chieftains and warlords and generals and narco-traffickers [and guerrilla groups] and … Venezuela becoming like a tapestry of different power centres,” the country’s former trade minister, Moisés Naím, told the Guardian last week.

Eric Farnsworth, a former US diplomat and vice-president of the Council of the Americas, said: “I think there is potential for actual chaos on the ground.

“Things on the ground have been very bad. Citizens have been leaving. But what we haven’t seen is a breakdown of civil authority … I think you could have security forces fighting each other. You could have further street protest and I think we have to be very mindful that Caracas – where everybody is focused – that is only one part of the country.

“I’m not willing to commit at this stage that [civil war] is where Venezuela is heading but I think that is one possible scenario,” Farnsworth added.

However, in an interview with the Guardian, Guaidó played down those fears.

“I don’t think we will reach that point. The idea is to increase pressure,” he said.

On Monday activists said at least 44 people had already been killed by security forces since Venezuela’s latest political upheaval began one week ago.

“What we are witnessing today in Venezuela in terms of human rights is a horror,” said Ana Leonor Acosta, a human rights lawyer, claiming “a massacre” was unfolding.

Alfredo Romero, a prominent human rights defender who runs the Foro Penal group, said 850 protesters had been taken into detention since 21 January. Romero said they included 77 minors, some as young as 12.

Addressing members of Venezuela’s security forces at a press conference, the opposition lawmaker Delsa Solórzano said her message was: “Stop repressing.

“Join democracy, put yourselves on the right side of history,” Solórzano added.