The European Union criticised Nicaragua's decision to expel its ambassador and break relations with the Netherlands, the bloc's foreign policy chief Josep Borrell said on Sunday.

President Daniel Ortega's leftist government is facing mounting diplomatic pressure over what the United States has called a dramatic deterioration of human rights -- which has seen the jailing of dozens of political opponents, students and journalists.

"The EU profoundly regrets and rejects this unjustified and unilateral decision," Borrell said of the expulsion, also expressing "unwavering support" for the Netherlands.

"These hostile, unwarranted actions" would not only effect relations between Nicaragua and EU but would lead to Managua's further international isolation, said Borrell.

The bloc will respond in a "firm and proportional manner", he added.

"The current political crisis in Nicaragua should be resolved through genuine dialogue between the government and opposition."

The European Union's envoy, Bettina Muscheidt, left Nicaragua Saturday a day after the authorities there declared her persona non grata.

Managua cut ties with the Dutch government on Friday evening, describing The Hague as "interventionist" and "neocolonialist" after its ambassador, Christine Pirenne, said her country would not fund the construction of a hospital.