Italy's Prime Minister Silvio Berlusconi called Friday for a new strategy in Afghanistan so foreign troops can leave, as the killing of six Italians stepped up pressure on his government. Berlusconi said more responsibility must be taken up by the Afghan government as Italy ordered national tributes to the six soldiers killed in a suicide bomb attack in Kabul on Thursday. A leader of a key member of the ruling coalition has demanded that Italy's 3,250 troops be withdrawn from Afghanistan before the end of the year. Berlusconi said 500 troops sent to Afghanistan for the country's election would be brought back but Italy could only end its Afghanistan deployment with the agreement of its NATO partners. 'We are keen to bring our boys home as soon as possible,' Berlusconi said before an EU summit in Brussels on Thursday. 'This is something that we cannot decide alone, because otherwise we would affect the confidence of other countries present there.' On Friday he added that the West needed a strategic change in Afghanistan. 'We have to develop a transition strategy to transfer more responsibility to the government of Hamid Karzai,' Berlusconi said during a visit to the Italian chiefs of staff. 'There must be a programme which strengthens the capacity of the Karzai government to guarantee security in the country and at the same time allows allied troops to reduce their numbers.' Defence Minister Ignazio La Russa said it would be 'a mistake' to discuss dates for a return until NATO and the United Nations had decided it was safe. A day of national mourning was ordered for the funerals of the six men on Monday, with a minute of silence in schools and public administrations nationwide, ANSA news agency reported quoting government sources. The national Olympic committee said there would be a minute's silence at all sporting events this weekend. The bodies of the six are to be flown back to Italy on Saturday, the military said. Their portraits were spread over the front pages of nearly every newspaper, even the main sports daily Gazzetta dello Sport, on Friday. The deadly attack has however opened up a new front of political turbulence for Berlusconi, already struggling with record low opinion poll ratings over his own private life and tensions within his government. Italian media highlighted the divisions between Berlusconi and nationalist leader Umberto Bossi, head of his coalition partner the Northern League, over the troop deployment. Reforms Minister Bossi said: 'The mission in Afghanistan is finished. The attempt to bring democracy to Afghanistan has failed. I hope that by Christmas they (the soldiers) will all be home.' 'The majority appears divided,' said the Rome daily Il Messaggero. 'One thing is certain. The Afghan question, if it is not quickly defused, risks complicating the future of the governing parties,' commented the independent La Stampa. Italy is the sixth biggest contributor to more than 100,000 NATO and US-led forces fighting in Afghanistan, which has faced an increasing number of Taliban attacks. Foreign military deaths in Afghanistan are at record levels -- 357 this year, according to icasualties.org -- and the mounting number has sent support for the war plummeting in Europe and the United States. However French Defence Minister Herve Morin, on a visit to Afghanistan, called on Italy 'not to give in to hasty emotion' by withdrawing troops. 'I understand very well the sadness, the sorrow and the emotion of the Italian people expressed by Sivlio Berlusconi but, at the same time, I want to say that one should not give in to hasty emotion,' he said. 