Argentine President Javier Milei and his vice-president, Victoria Villarruel, have engaged in a bitter public war of words over plans to increase pensions.

Milei shared posts on X in which his running mate had been called “stupid” and described as “a traitor”, and in response Villarruel told the president to “grow up”.

The president’s anger was triggered by a heavy defeat in Congress on Thursday, when the Senate approved motions aimed at boosting pensions and increasing disability allowances – which Milei had vehemently opposed.

Milei said he would veto the pension hike, arguing that the extra expenditure threatened his fiscal surplus, and blamed Villarruel for allowing the vote to proceed.

In Argentina, the country’s vice-president also acts as the president of the Senate.

It was in this role as Senate leader that Villarruel allowed the debate on the emergency pension hike to proceed, even though senators allied with the government boycotted the session.

With government-aligned senators absent, the motion passed with 52 votes in favour and four abstentions.

Its backers argue that higher payments are essential in order for pensioners to make ends meet.

But President Milei says it goes counter to his promise to eliminate Argentina’s chronic fiscal deficit and bring down inflation.

In January, Milei scored a major economic victory when it emerged that 2024 was the first year in more than a decade that Argentina had registered a budget surplus.

Last month also saw the country’s monthly inflation rate drop to 1.5%, the lowest it has been in more than five years.

But the austerity measures that helped the libertarian president lower the deficit and drive down inflation have also triggered protests, with pensioners holding weekly rallies outside Congress.

Following the approval of the motion on Thursday, President Milei was quick to announce that he would block the pension hike.

“I bet a hundred thousand to one that you all know what I’m going to do. You know what? We’re going to veto it. And if, by some chance, which I don’t believe will happen, but if the veto is overturned, we will take it to court,” he said.

But he also turned on his vice-president, reposting a comment on X in which she was labelled a “traitor, a demagogue and stupid in economic terms”.

Villarruel responded on Instagram arguing that pensioners and people with disabilities “could not wait” any longer for their payments to be raised and suggested the president should make savings by spending less on the intelligence services and on his travels.

Since becoming president in December 2023, Milei has travelled abroad extensively.

In one of the most publicised events, he wielded the chainsaw which has become emblematic of his government cuts before handing it to Elon Musk at the US Conservative Political Action Conference.

Villarruel also urged the president “to speak and act like an adult” in responses she gave her critics on Instagram.