ATHENS ?- Tension is flaring in Greece as thousands of protesters encircled the parliament Sunday afternoon ahead of a crucial vote after midnight on the new debt deal reached with international lenders last week to avoid a Greek default next month.

A policeman and a photo journalist were slightly injured, according to local media, when protesters clashed with anti-riot police during a mass anti-austerity rally staged by labor unions and Leftist parties.

According to estimates, some 25,000 people joined the mobilization chanting slogans such as "We say no to the thieves who condemn us to poverty."

Tear gas was used to dispel hooded protesters, who have started pelting rocks and petrol bombs against police forces.

Some peaceful demonstrators were treated with respiratory problems, Greek media reported. Amongst them were renowned composer Mikis Theodorakis, best known worldwide for the music of the film "Zorbas the Greek" and Manolis Glezos, a Left-wing former MP, who during the World War II?tore down the Nazi flag from the Acropolis hill.

Tension is rising inside the assembly as well, as lawmakers debate the tough conditions of the second 130-billion euro (171.43 billion US dollars) ?bailout loans package European counterparts and International Monetary Fund will grant Greece in exchange of further austerity and reform measures.

Prime Minister Lucas Papademos, Finance Minister Evangelos Venizelos and the leaders of the socialist PASOK and conservative New Democracy (ND) party supporting the interim administration have warned over the past few hours in dramatic speeches that a negative vote could lead to a catastrophic disorderly bankruptcy.

Recession-hit citizens are divided in front of the major dilemma, according to an opinion poll released on Sunday. Some 48 percent of respondents in the survey by local daily "Paron" (Present) chose default rather than the painful conditions of the agreement versus a 38 percent who supported the deal. Six out of ten respondents called for a snap general election.

"There is always a democratic way to resolve problems. Peoples should be allowed to make the critical decision for their future. Both paths are difficult, but it is at least offensive when creditors put so much pressure on a nation," young student Christina Terzi told Xinhua outside the parliament.

Under heavy pressure by disgruntled citizens, as a total of six ministers have quit the government since Thursday and some 20 deputies of the two coalition parties have said they will oppose the measures, an increasing number of MPs raise severe doubts over the deal.

Political analysts in Athens nevertheless expect that more than 200 lawmakers at the 300-member strong parliament will vote in favor of the bill during the critical roll-call process on Sunday night.

If the Greek parliament will not ratify the deal, the debt-laden country which relies on international aid to keep afloat since 2010, could financially collapse on March 20.