Two Italian police officers were shot and wounded on Sunday outside the prime minister's office in Rome at the same time as Prime Minister Enrico Letta's new government was being sworn in just a mile away.
It was not immediately clear whether the attack was linked to the launch of the new government, but the episode came at a time of bitter political division with rising social tensions exacerbated by a long economic slump.
Letta, 46, the moderate deputy head of the Democratic Party (PD), on Saturday ended two months of political stalemate following February's inconclusive election when he united former political rivals in a broad coalition government.
The mix of center-right and center-left politicians and unaffiliated technocrats was largely welcomed in Italy's mainstream press on Sunday, especially for the record of seven female ministers and the relatively young average age.
However, the political risks that Letta faces were spelled out on Sunday by a close ally of center-right leader Silvio Berlusconi who is a core stakeholder in the government.
Renato Brunetta, lower house leader of Berlusconi's People of Freedom party (PDL), said the government would fall unless Letta promised in his maiden speech to urgently abolish an unpopular housing tax and repay the 2012 levy to taxpayers.
Letta is expected to set out his government's plans in parliament on Monday and will then need to win a vote of confidence in both houses to be fully empowered.
"If the prime minister doesn't make this precise commitment we will not give him our support in the vote of confidence," Brunetta told daily Il Messaggero.
Brunetta, who was himself a candidate for the post of economy minister, said that during negotiations for the formation of the government Letta had "given his word" on the abolition and repayment of the tax, which would leave an 8 billion euros hole in public accounts.
However, on Sunday attention was focused on the dramatic shooting outside Palazzo Chigi, the prime minister's official residence, with several politicians warning that the fevered political climate may have contributed to the episode.
Luigi Preiti, in his forties, from the southern Italian region of Calabria, was arrested.
Having fired several shots at the two police on duty outside the prime minister's office, he shouted "shoot me, shoot me" to other police officers nearby, police said.
One of the two officers was shot in the neck and was in a serious, but not life-threatening condition, while the other officer was shot in the leg and less seriously hurt.
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