The results, with almost all precincts counted, were a blow for pro-Western Georgians who had cast the election as a choice between a ruling party that has deepened ties with Russia and an opposition aiming to fast-track integration with Europe.
President Salome Zourabichvili urged people to take to the streets to protest against the results of Saturday's disputed parliamentary election, which the electoral commission said the ruling party had won.
The ruling Georgian Dream party, of which Zourabichvili is a fierce critic, clinched nearly 54 per cent of the vote, the commission said, as opposition parties contested the outcome and vote monitors reported significant violations.
The European Union and United States call for an investigation of reported election irregularities. (AP PHOTO)
On Sunday, US Secretary of State Antony Blinken said the United States joined calls from observers for a full probe.
"Going forward, we encourage Georgia's political leaders to respect the rule of law, repeal legislation that undermines fundamental freedoms, and address deficiencies in the electoral process together," Blinken said in a statement.
Earlier, the European Union urged Georgia to swiftly and transparently investigate the alleged irregularities in the vote.
"The EU recalls that any legislation that undermines the fundamental rights and freedoms of Georgian citizens and runs counter to the values and principles upon which the EU is founded, must be repealed," the European Commission said in a joint statement with EU foreign policy chief Josep Borrell.
Zourabichvili, a former Georgian Dream ally who won the 2018 presidential vote as an independent, urged Georgians to protest in the centre of the capital, Tbilisi, on Monday evening to show the world "that we do not recognise these elections".
For years, Georgia was one of the most pro-Western countries to emerge from the Soviet Union, with polls showing many Georgians disliking Russia for its support of two breakaway regions of their country.
Russia defeated Georgia in their brief war over the rebel province of South Ossetia in 2008.
The election result poses a challenge to the EU's ambition to expand by bringing in more former Soviet states.
Last week, Moldova narrowly approved its EU accession in a vote Moldovan officials said was marred by Russian interference.
