Leaders of the powerful G7 nations raced for a joint response to spiralling tension over the eurozone debt crisis and downgrade of the US credit rating ahead of the opening of markets on Monday. After stock markets suffered their worst falls since 2008 last week,vacationing leaders scrambled in a flurry of phone calls from London to Paris to Washington to salvage confidence before the clock strikes in New Zealand,the first market to open in Asia. Finance Ministers and central banks from the G7 nations,Britain,Canada,France,Germany,Italy,Japan and the United States are to hold a telephone conference call and possibly issue a joint statement today,Jiji Press said in Tokyo. Officials remained tight-lipped,however,on plans to stave off a global meltdown,with the European Central Bank (ECB) notably refusing to confirm reports of today evening telephone conference call between European central banks. At stake is whether the Frankfurt bank will step into the market to buy back debt piled up by Italy,the eurozone's third largest economy and latest potential victim of the rumbling euro crisis,also threatening Spain. It last week saw its borrowing costs spiral to record highs due to a loss of investor confidence over its debt mountain,120 percent of its GDP,as well as poor economic growth prospects and political tension. Buckling to ECB demands to first step up reforms and slice its deficit,Prime Minister Silvio Berlusconi this weekend said lawmakers would be called back early to rush through austerity measures,including a constitutional amendment to force governments to keep balanced budgets.