The European Central Bank is due to hold emergency talks on whether to start buying Italian debt to contain spreading turmoil on financial markets.
The BBC’s Business Editor Robert Peston says the ECB is split on the move.
Growing worries over debt in the eurozone and the US caused sharp falls on world stock markets last week.
Finance ministers from the G7 major economic powers are also to hold emergency talks on how to calm the markets before they reopen on Monday.
The main council of the ECB will hold a telephone conference on Sunday afternoon, the BBC has learned.
According to an ECB source cited by Reuters news agency, the bank’s president Jean-Claude Trichet wants a final decision on whether to buy Italian debt to be made at the meeting.
Italy is the latest and biggest economy to be hit by the eurozone crisis.
The price Italy pays on its government bonds has shot up amid growing doubts it can keep its debt level so high while economic growth is so slow.
Spain, too, has been caught up in the crisis – hammered by high unemployment, high government debt and anaemic growth.
The high levels of debt coupled with low growth and an uncertain response among eurozone leaders to the crisis has sparked fears that both countries could become engulfed in the same cycle which has led to Greece, the Irish Republic and Portugal already being bailed out.
Last week, European Commission President Jose Manuel Barroso said authorities in the eurozone were failing to prevent the sovereign debt crisis from spreading.
On Friday, Italian Prime Minister Silvio Berlusconi said he was bringing forward austerity measures and would balance the government budget by 2013, one year ahead of schedule.
Last week, the gap between German bonds – seen as the safest in Europe – and Spanish and Italian debt reached a record high since the euro was introduced in 1999.
There have been rumours that the ECB was preparing to buy Spanish and Italian bonds to try to help those countries. Last week the ECB bought Irish and Portuguese bonds but did not include Spanish and Italian debt in its purchases.
The BBC’s Business Editor Robert Peston says the ECB’s governing council is divided on whether to buy Italian bonds.
A decision not to buy would risk further turmoil in share and bond markets on Monday, he says.
Some analysts argue that investors expected the bank to buy Italian and Spanish debt soon after the eurozone leaders summit on 21 July, and the fact that it has not has undermined confidence in the markets.
Finance ministers and central bankers from the G7 are to hold emergency talks by telephone before markets open in East Asia on Monday morning, aiming to craft a global response on the eurozone debt crisis and ease fears over rating agency Standard & Poor’s downgrading of US credit-worthiness.
The rating agency Standard & Poor’s (S&P) on Friday downgraded America’s top-notch AAA rating to AA+.
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S&P ratings (selected)
AAA: UK, France, Germany, Canada, Australia
AA+: USA, Belgium, New Zealand
AA-: Japan, China
S&P, one of the world’s three major rating agencies, failed to be impressed by a last-minute deal in the US last week to raise the US debt limit by up to $2.4tn (£1.5tn) from $14.3tn.
It staved off a potential US government default on its debt but was only achieved after months of wrangling between Democrats and Republicans in Congress.
The credit rating downgrade is seen as a major embarrassment for President Obama’s administration. It could also raise the cost of US government borrowing.
An economic adviser to the White House condemned the S&P move.
“It smacked of an institution starting with a conclusion and shaping any argument to fit,” said Gene Sperling, the head of President Obama’s National Economic Council.
White House spokesman Jay Carney said on Saturday that last week’s debt deal had been “an important step in the right direction”, but that “the path to getting there took too long and was at times too divisive”.