Protesters firing tear gas disrupted the inauguration ceremony of Kosovo President Hashim Thaci on April 8.
Guests at the open-air event in central Pristina coughed and wiped their eyes as tear gas canisters were set off just before Thaci gave his inaugural speech to a 1,000-strong audience.
Police said 12 people were arrested.
The public transfer of power from Thaci's predecessor Atifete Jahjaga came a day after he took the oath of office in parliament amid protests.
The opposition in the majority ethnic Albanian state accuses Thaci of helping clinch an agreement brokered by the European Union in 2015 that gives a small Serb minority more power over local government decisions and raises the possibility of financing from Belgrade.
Thaci, who led a guerrilla insurgency against Serbian forces in 1998-99, went ahead with his ceremony despite the tear gas, saying he wanted dialogue both with Serbia and his domestic critics.
"Kosovo and Serbia should pass from the phase of normalization of their relations to the phase of reconciliation between two countries," he said.
Kosovo declared independence in 2008 and is recognized by more than 100 countries, but not by Serbia.
