Two men on a motorcycle have shot dead a senior adviser to the Italian government in what Prime Minister Silvio Berlusconi has denounced as an act of political "terrorism".
Economist Mr Marco Biagi, who helped Mr Berlusconi's centre-right government draft controversial new labour reforms, was shot in front of the home he shared with his wife and son in Bologna. He died as he was being taken to hospital.
The killing revived fears of a resurgence of the politically motivated violence Italy suffered in the 1970s and 1980s.
"Once again...terrorism surfaces and represents a real danger that has to be confronted with all necessary force," Mr Berlusconi said in a statement.
"The murder of Marco Biagi, a highly valued economist who was helping the government define its labour policy, grieves all Italians," he added.
Although no one claimed immediate responsibility for the killing, anti-terrorist experts were sent in and Interior Minister Claudio Scajola cut short a trip to the United States.
Bologna's prosecutor general indicated he believed the murder was tied to contested government plans to overhaul labour laws, which are aimed at making it easier to hire and fire certain categories of workers.
Mr Biagi’s murder came a month after a small bomb exploded outside the Interior Ministry in Rome and followed a warning by the justice ministry that political extremism was on the rise.
Mr Sergio Cofferati, the leader of Italy's largest union, denounced Mr Biagi's killing and held emergency talks with other labour leaders to discuss the crisis.
The killing echoed the 1999 murder of another senior Labour Ministry aide, Mr Massimo D'Antona, who worked for the then centre-left government.
A group calling itself the Red Brigades, a guerrilla movement thought to have been eliminated more than a decade ago, later claimed responsibility for the shooting.
Last year, police arrested eight suspected far-left activists in connection with D'Antona's assassination.