The negotiations on a joint rescue for debt-hit Greece would be concluded in the coming days, European Commission President Jose Manuel Barroso said in a statement released on Thursday.

Barroso said the Commission is making "solid" and "rapid" progress with the European Central Bank (ECB), the International Monetary Fund (IMF) and the Greek government to finalize the Greek rescue package.

"The Commission expects this work to be finalized in the coming days," he said.

Athens is facing a looming deadline to pay back 8.5 billion euros (11.3 billion U.S. dollars) by May 19.

Confronted with unprecedented borrowing costs, Greek Prime Minister George Papandreou formally asked for the activation of a joint aid program by eurozone governments and the IMF on Friday.

Eurozone finance ministers agreed on a detailed aid package for Greece earlier this month, under which eurozone countries would provide loans to Greece on a bilateral basis, with a total amount of 30 billion euros (40 billion dollars), while the IMF was expected to release further 10 to 15 billion euros (10.3 to 19.9 billion dollars).

Talks on the final details of the joint aid were still going on among the EU, the IMF and the Greek government as the deepening crisis sent global stock markets and the euro plunging in recent days.

There is an increasing concern that Athens may not get financial support in time and be forced to delay or limit its repayment of maturing government bonds through debt restructuring.

Barroso said the eurozone countries, the Commission, the ECB and the IMF are determined to guarantee the overall financial stability of the eurozone, and all eurozone countries are finalizing the procedures that will allow them to provide financial support to Greece as necessary.

"There is no doubt that Greece's needs will be met in time," he said.

Barroso downplayed the possibility of debt restructuring for Greece.

"Debt restructuring in a euro-area member state is not an option and is not going to be part of the joint program," he said.

Barroso also issued a veiled attack on credit-rating agencies after they downgraded the credit ratings of Greece, Portugal and Spain in the past days, which strengthened fear that the Greek debt crisis may be spreading in the eurozone.

He said that the EU has put into place a regulatory framework on credit-rating agencies and would continue to watch closely the behavior of the financial markets during the crisis.

A Commission spokeswoman on Thursday urged credit rating agencies to act "in a responsible way" so as not to add fuel to the fire.