ZAGREB -- A car-bomb exploded Thursday outside the offices of a Croatian weekly newspaper in central Zagreb, killing the high-profile journalist who owned the publication and its marketing director.

"We have established the identities of those killed. They are Ivo Pukanic and Niko Franjic," police spokesman Krunoslav Borovec told reporters.

Pukanic had been considered one of Croatia's most controversial journalists and his murder came only months after he survived a gun attack in downtown Zagreb in April. The attacker was not found.

Croatian President Stipe Mesic fiercely condemned the attack while Prime Minister Ivo Sanader called a special meeting of the Balkan country's national security council on Friday to discuss Zagreb's growing mafia-style crime wave.

"With tonight's assassination of journalist and publisher Ivo Pukanic and Nacional marketing expert Niko Franjic, terrorism has entered the streets of Croatia's capital," Mesic said in a statement.

"The criminal underground has confronted the rule of law and the whole system with a challenge we have not encountered so far," he said.

There was no immediate claim of responsibility for the blast outside the Nacional weekly's offices in central Zagreb.

Police said that for the time being they did not eliminate any possible motive for the attack.

"During the past few days Pukanic did not report to police any threat and did not provide any indication that something like this could happen," Borovec, the police spokesman, said.

Two other people were injured in the blast which completely destroyed the car under which the explosive device was placed.

The blast occurred at 6:20 pm (1620 GMT), according to television reports which broadcast footage of the car's burnt-out wreckage.

The area was cordoned off by police, an AFP correspondent at the scene said.

The Croatian Journalists' Association (HND) voiced outrage at the murder and called on the authorities to "immediately declare a war on criminals and murderers."

"What has occurred is horrible and it shows that crime has severely expanded in Croatia," the HND said in a statement.

A number of attacks have occurred in the Croatian capital in recent weeks, including the mafia-style killing of the daughter of a prominent lawyer earlier this month.

Sanader sacked his interior and justice ministers and his police chief after the suspected mafia killing.

"The government and all institutions will even more decisively and more strongly fight against organized crime and terror which is entering Croatian streets," Sanader said after Thursday's murder of Pukanic and Franjic.

"We will not allow Croatia to become another Beirut," he added.

Tackling organized crime is one of the criteria Croatia must meet on its path towards membership of the European Union.

The HND journalists' association said Pukanic, 47, was the first Croatian journalist to be killed locally since Croatia's 1991-1995 war.

The Nacional owner hit the headlines in 2003 when he published an interview with former Croatian general Ante Gotovina, two years after he fled following a war crimes indictment by The Hague-based UN tribunal.

During the past few years, independent media were accusing him of being close to some criminal circles.