Nicaragua is closer to “total economic chaos” and a new civil war than ever before, a supreme court judge has warned in a searing resignation letter to President Daniel Ortega.

In a three-page dispatch sent to the former revolutionary icon this week, Rafael Solís accused Ortega of transforming the Central American country into “a state of terror” after an uprising against him began last April.

The judge – a longtime associate of the 73-year-old Sandinista – claimed peaceful protests had been repressed “with bloodshed and fire” and heavily armed paramilitaries unleashed to sow fear.

An ongoing “war” on the press – which last month saw armed police seize the newsroom of one of Nicaragua’s top independent media outlets – meant journalists now faced a stark choice: exile or jail.

In his letter, published on Thursday, Solís called himself “an ex-Sandinista militant” and said he was resigning because Nicaragua had become a dictatorship resembling an absolute monarchy with two kings: Ortega and his powerful first lady and vice-president, Rosario Murillo.

The couple’s refusal to seek a peaceful solution to the crisis through dialogue with the opposition meant conflict now loomed: “I do not desire a civil war for Nicaragua but it’s clear to me this is the path you are going down.”

Solís argued that the army’s failure to disarm pro-Ortega paramilitary groups blamed for scores of deaths meant it was “logical to expect the opposition groups will seek to arm themselves and the country will regress 40 years”.

“God willing a miracle will occur,” he concluded. “God save Nicaragua.”

Activists and members of Nicaragua’s opposition celebrated the defection of a member of Ortega’s inner circle as a major blow to his rule. Solís is a veteran Sandinista and Ortega confidant and was reportedly best man at Ortega’s 2005 wedding to Murillo.

“Increasingly isolated, all the regime has against its people are weapons,” tweeted Amnesty International’s America’s chief, Erika Guevara-Rosas.

Ortega has blamed the deadly violence that has gripped Nicaragua on “hate-sowing coup-mongers” with foreign backing. But his former loyalist rubbished those claims in his letter: “There was no such coup, nor any external aggression, just the irrational use of force.”