Thousands of Romanian protestors working abroad flocked from across Europe to line the streets of the capital, to demonstrate against corruption in the country and the ruling Social Democrat Party (PSD).
Around 7,000 protestors waved Romanian and European Union flags and chanted “party of thieves” as they called for the government to resign, with protestors joining the rally as it continued into the evening.
Tens of thousands also staged peaceful protests in other Romanian cities.
But protesters scuffled briefly with riot police when they tried to break through a security line guarding the government building in Bucharest.
Some protestors threw bottles and other objects at police, who used tear gas and water cannon in retaliation, resulting in people on both sides requiring brief medical attention.
Police claimed groups of «provocateurs» were present in the square. More than 100 people needed medical attention.
The protestors were organised by Romanian expat groups operating overseas.
An estimated 3 to 5 million Romanians are working and living abroad, the World Bank has said, or about a quarter of the European Union state’s overall population.
Romanian workers abroad sent home just under $5billion (£3.9billion) in 2017.
The money provides a lifeline for rural communities in one of the EU’s least developed countries.
Among the protesters was truck driver Daniel Ostafi, 42, who moved to Italy 15 years ago in search of a future he says Romania could not offer his family.
Mr Ostafi said: «I left to give my children a better life, which was not possible here then.
«Unfortunately, it is still not possible, the … people who govern us are not qualified and they are corrupt.”
The PSD pushed changes to the criminal codes through parliament that have raised concerns from the European Commission, the U.S. State Department and thousands of magistrates. The changes are pending Constitutional Court challenges.
Romania ranks as one of the EU’s most corrupt states and Brussels keeps its justice system under special monitoring.
Several politicians from the ruling coalition derided the rally in the run up, saying they did not understand why the diaspora would protest.
Mihai Podut, 27, a construction worker who left in 2014, first for France and later Germany, said: «Almost all of the public sector is malfunctioning, it must be changed completely and replaced with capable people.
“I would ask our ruling politicians to switch places with us, work the way we do and see what that is like.»