It said suspected gangster bosses Dusan Spasojevic and Mile Lukovic were killed near Belgrade while resisting arrest.

"In tonight's arrest action, the leaders of this gang were giving armed resistance and police had to use force," the statement on BK television said.

The government has named them as two out of three leaders of a powerful criminal group known as the Zemun gang which it says organized and carried out the assassination of Djindjic on March 12 in a bid to spread chaos and avoid arrest.

It said earlier this week that the suspected assassin, a deputy commander of a special police unit set up during the rule of Slobodan Milosevic, had been arrested.

The Interior Ministry statement did not mention the third alleged leader of the Zemun gang, former special police commander Milorad "Legija" Lukovic.

The authorities say the Zemun gang is a powerful drug cartel linked to Milosevic-era state security officials and led by Legija and the two men killed on Thursday.

Djindjic, who played a key role in ousting of Milosevic in 2000 and enraged nationalists by sending him to The Hague the following year to stand trial, was shot dead by a sniper outside the main government building just over two weeks ago.

He fought to transform the impoverished republic from an international pariah to a Western-style democracy, and vowed to clamp down on organized crime that flourished during Milosevic's turbulent decade in power.

The government declared a state of emergency after the assassination, giving police extra powers to hold people and raid houses. Police have since detained more than 1,000 people in their war on organized crime.