Firebombs thrown by incensed anti-austerity protesters exploded in front of Greece's parliament Wednesday as anger over the new bailout deal spilled onto the streets of Athens.

The bill was passed with 229 votes in favour despite the split within the left-wing ruling party Syriza, with 64 voting against and six abstaining, France 24 reported.  

The ruling Syriza party passed the bill thanks to support from pro-European opposition parties, as a large group of government lawmakers voted against the measures, including the head of parliament Zoe Constantopoulou.

Addressing parliament before the vote, Prime Minister Alexis Tsipras said that his government had no choice but to implement austerity measures to unlock a new bailout for Greece worth up to 86 billion ($94 billion), according to Agence France-Presse.

"We don't believe in it, but we are forced to adopt it," Tsipras said ahead of the vote early Thursday, according to DW.

However, citizens who voted only two weeks before saw the governments vote as an act of betrayal.

As police used pepper spray and gas to stop a crowd breaching a security line blocking off the road to the prime minister's office, one man in a balaclava shouted, "We have been betrayed!"

The violence erupted during a rally of 12,500 people who opposed the passage of the reforms. Many argue that Greece cant afford to face any more cuts or tax hikes after experiencing a 6-year-long recession, according to Newsmax.

Officers could be seen dragging protesters away in handcuffs and police sources report that about 40 people have been detained.

As police forced rioters away from parliament, some broke off from the crowd and vandalised ATMs and broke a few shop windows.

Conflicts with police, which used to be common in protest marches in Greece, have been very rare since Syriza came to power in January, France 24 reported.

Protesters marched with banners right before the clashes, some of which read "Cancel the bailout!" and "No to the policies of the EU, the ECB and the IMF."