About 200 people have been arrested in the assassination of Serbian Prime Minister Zoran Djindjic, B92 radio reported Thursday.

Djindjic died Wednesday. He was shot twice in the chest and back as he stepped out of his armoured car and entered a government building in Belgrade. According to Daily Politika, he was shot by one or more snipers from a distance of 200 metres.

Earlier reports had put the number of arrests around 40, but in an interview with B92, acting prime minister Nebojsa Covic reportedly said about 160 more had been detained. An excerpt of he interview was published on B92's website and the full version was due to air later Thursday.

The report also said Covic confirmed media reports that police had brought in two Milosevic-era state security chiefs, Jovica Stanisic and Franko Simatovic, for questioning.

Earlier Thursday, Deputy Prime Minister Zarko Korac told Belgrade's B92 radio that the criminal gang Zemun was behind the assassination.

"(Zemun) is probably the most organized gang in the Balkans," Korac said.

Korac named numerous suspects, among them an associate of the state security service who is accused of participating in other assassinations and a former special operations unit commander.

Djindjic, the man pivotal in the deposition and arrest of former Yugoslav president Slobodan Milosevic, was a pro-western leader who made enemies by pushing for the arrest of mobsters and war crimes suspects.

An earlier government statement said the assassination was aimed at causing "chaos, lawlessness and fear in the country," but Korac vowed Serbian reforms aimed at eliminating the country's mafia-like underworld would not be derailed.

The government statement also listed 20 alleged leaders of the Zemun, including Milorad Lukovic, former commander of a special police unit, and Dejan Milenkovic, who police accused of trying to kill Djindjic by driving his truck into the motorcade transporting the prime minister. The convoy narrowly avoided a collision. At the time, Djindjic blamed organized crime for the incident.

Acting President Natasa Micic declared a state of emergency Wednesday following Djindjic's murder, which leaves Serbia with neither a prime minister nor an elected president. Officials said Covic, who was one of the country's deputies, would step in as acting prime minister.

On Wednesday, police with machine guns cordoned off the streets and searched vehicles near the murder scene, looking for the assassins. All flights from Belgrade airport were suspended.

Journalist Milicia Lenasi said the people of Serbia were in shock.

"No one thought his life would end the way it did today," she told CTV Newsnet. "Despite the fact that his reforms were not popular because they were hard economically, he was getting more popular every day, because he was seen as the only person who was really working for the good of the country."

The European Union condemned the killing and praised Djindjic's work to put his country on the path to EU membership.

"It is a tragedy," said EU foreign policy chief Javier Solana, "He was a personal friend and a friend of Europe."

Greece, which holds the EU's rotating presidency, said organized crime was Serbia's public enemy number one.

"As the presidency I would like to say we will make every effort to work for stability and safety in the Balkans," Greek Foreign Ministry spokesman Panos Beglitis told reporters Thursday.

Croatian President Stjepan Mesic described the assassination -- the seventh political killing in three years -- as "an act of madness."

"This is not good for Serbia, not good for us in the neighborhood. Serbia has been through a difficult period ... and this assassination will slow down its progress towards democracy," he told reporters.

With a report from Reuters