Argentina and Mexico have recalled their ambassadors to Nicaragua for consultations in response to President Daniel Ortega's mounting crackdown on the opposition, a joint statement said on Monday.
The two countries voiced concern about "the worrying political-legal actions carried out by the Nicaraguan government in recent days that have put the integrity and freedom of various opposition figures at risk."
Argentina and Mexico will continue to press for "the full respect and promotion of human rights" as well as civil and political liberties, the statement said.
They offered to help foster a dialogue to resolve the situation in the Central American country, which is scheduled to hold presidential elections in November.
The diplomatic move comes less than a week after both Argentina and Mexico were strongly criticised by international human rights organisations, including Amnesty International and Human Rights Watch, over their failure to back a Organisation of American States (OAS) resolution criticising the arrests.
Nicaraguan authorities have arrested 17 opposition figures this month, including five potential presidential candidates, eliciting international condemnation and fresh US sanctions.
On Sunday night the journalist and presidential hopeful Miguel Mora was arrested at his home for "inciting foreign interference in internal affairs and requesting military intervention," according to authorities.
The Nicaraguan government says the detainees are "usurpers" funded by the United States to topple Ortega.
The 75-year-old governed Nicaragua from 1979 to 1990, returned to power in 2007 and has won two successive reelections since then.
He is widely expected to seek a fourth term in the upcoming November elections, though he has not yet confirmed that he will.