Moldova's political crisis has escalated, with an interim president calling snap elections on 6 September.
Pavel Filip, who was appointed by the Constitutional Court to succeed Igor Dodon, also dissolved the parliament.
But the parliament declared Mr Filip's moves illegal, saying the country's state institutions "have been seized".
The stalemate follows general elections in February, where no clear winner emerged between rival pro-EU and pro-Russian parties.
There are now fears that the prolonged political crisis could lead to violent clashes on the streets.
Moldova, a former Soviet republic, lies between the EU and Ukraine and is one of Europe's poorest countries.
What's happening in Moldova?
On Sunday, the Constitutional Court in the capital Chisinau relieved Russia-backed President Dodon from his duties because of his refusal to dissolve the parliament.
The court also appointed Mr Filip, a pro-EU former prime minister, an interim president.
This comes a day after the pro-EU Acum political bloc and Mr Dodon's Socialists struck an unlikely deal and formed a compromise government.
In parliament, lawmakers also declared that Moldova's state and legal institutions "have been seized" by influential oligarchs, calling for the resignation of several top officials.
But the formation of the new government took place a day after a constitutional deadline for this expired.
So, Mr Filip's Democratic Party - which is led by Moldova's richest man Vladimir Plahotniuc - filed a legal challenge which was backed by the Constitutional Court.
In response, Mr Dodon described this as desperate steps to usurp power.
Is this political tug-of-war unusual?
No.
In Moldova, a parliamentary republic, the rival political camps frequently clash with one another.
Therefore the country - where the electorate is split between EU- and Russia-sympathisers - has witnessed several such crises in recent years.
They usually end up in holding snap elections, but results are often inconclusive.