Speaking ahead of talks with Greek Prime Minister Alexis Tsipras in Brussels on Friday, Juncker (seen above right with Tsipras) said he was "not satisfied" with the progress made in agreeing the reforms that Athens must undertake in exchange for a four-month extension of its international bailout, but that he "excluded a failure."

"I'm not satisfied with the developments in recent weeks," Juncker said as he met Tsipras, adding that he would make a "certain number of proposals" to his "friend Alexis" during the talks.

His remarks come two days after technical talks resumed between Athens and the institutions providing the rescue package - the Commission, the European Central Bank (ECB) and the International Monetary Fund.

The international creditors have demanded a number of economic reforms from Athens in exchange for access to the 7.2 billion euros ($7.6 billion) still remaining in international aids.

EU officials say the measures outlined so far by the Athens government are insufficient.

However, Tsipras, who came to power in late January on the back of pledges to end bailout-related austerity measures, has insisted that Athens has started fulfilling its conditions for the bailout extension agreed last month.

"We are doing our part," he said earlier on Friday after talks with European Parliament President Martin Schulz. "We expect our partners to do their own part."

Greece has received two bailouts totaling 240 billion euros since 2010 to enable it to meet its debt obligations and avoid going bankrupt.

Growing support for the 'Grexit'

A poll published in Germany on Friday has meanwhile shown that more than half of Germans think Greece should leave the eurozone.

The Politbarometer survey released by public broadcaster ZDF showed that just 40 percent of people want Greece to stay in the currency union, down from 52 percent two weeks ago.

The poll also found that 80 percent of respondents thought that Athens is not acting reliably in its negotiations with eurozone partners, while only 14 percent believe it will implement the austerity and reform measures necessary to procure the bailout extension.

According to the survey, Chancellor Angela Merkel and Finance Minister Wolfgang Schäuble remained the country's most popular politicians, in stark contrast to their reputation in Greece, where they have become hate figures to many for their insistence on austerity and reform demands in return for aid.

tj/sms (AFP, dpa, AP)