In a coordinated move, European Union foreign policy chief Catherine Ashton called on Assad to step aside and said the EU was preparing to broaden sanctions against Syria.

French and German leaders disappointed financial markets this week, signalling that a common sovereign bond, if it ever comes, would be a long way off and that instead they were focusing their efforts on more economic integration.

Speaking shortly after her appointment as head of ETUC, Ségol insisted that the FTT should not be seen as a replacement for member states' contributions to the European budget.

"If we have an FTT it should be more for additional investment, growth and jobs, which is our priority, and not to replace income that should be there anyway," she said, alluding to the proposed EU budget for 2014-2020, presented by the European Commission on 29 June.

The sources, who spoke on condition of anonymity, said the United States also may lay out plans to impose additional US sanctions on Syria, whose government has engaged in a brutal crackdown against protesters seeking an end to the 41-year rule by Assad and his father, Hafez al-Assad.

The sources said that the US appeal could come on Thursday and would quickly be followed by similar calls from others, notably the EU.

The Association for Financial Markets in Europe (AFME), which represents top banks, also said yesterday (17 August) that a tax would simply bump up costs for a large section of European industry and hit growth.

Shares in stock exchange operators took a hit after French President Nicolas Sarkozy and German Chancellor Angela Merkel unveiled a plan on Tuesday to tax financial transactions.

The eurobonds debate overshadowed a Franco-German summit on Tuesday (16 August), with a growing body of economists saying the only way to ensure affordable financing for the bloc's most distressed countries would be for the euro area to pool its debt by issuing joint eurobonds.

BusinessEurope, the corporate lobby, has written to the European Commission demanding an EU passport for funds seeking to raise capital across borders as they argue that new rules for higher amounts of capital on banks' books will squeeze lending to start-ups.

In Europe, companies, and especially SMEs, depend mostly on national bank lending to access finance. 

Under heavy pressure to restore confidence in the euro zone following a dramatic market slump earlier this month, President Nicolas Sarkozy and Chancellor Angela Merkel vowed to stand shoulder-to-shoulder in defending the single currency.

The two leaders did not back joint euro bonds, seen by many as a solution to the euro zone's debt problems, saying this could only be envisaged as a longer-term option. They also stopped short of increasing the euro zone's EFSF rescue fund, which currently stands at €440 billion.

Israel announced on Monday (15 August) that approval had been granted to build 277 homes in a West Bank settlement, despite US and international pressure to curb expansion on occupied land and Palestinian preparations for a statehood bid at the United Nations.

"The Quartet is greatly concerned by Israel's recent announcements to advance planning for new housing units in Ariel and East Jerusalem," the mediating group said in a joint statement.

French President Nicolas Sarkozy and German Chancellor Angela Merkel are meeting in Paris to discuss what further measures they can take to contain Europe's debt crisis, which is now spreading to the continent's core.

Italy has been forced to ramp up its austerity measures and financial market jitters hit France last week, with French banks' shares subject to panic selling on rumours that the country could be next to lose its prized AAA debt rating.