SOFIA, Bulgaria (AP) -- Bulgaria's government said Tuesday it is withdrawing a controversial budget proposal after protests against it drew tens of thousands of people and saw clashes between police and protesters.

Opposition and business groups have warned that plans for higher taxes, increased social security contributions and spending increases could hurt investment and expand the shadow economy as the country prepares to join the eurozone at the start of next year.

The government first promised to withdraw the draft for through revision after protests last week, but later refused to do so, sparking protests in the capital, Sofia, and other major cities Monday night. Organizers said that 50,000 people attended the protest in Sofia.

The protest in Sofia, which was dominated by young people, was largely peaceful, but it was followed by violent clashes.

Jumping and chanting slogans like "We will not allow ourselves to be lied to; we will not allow ourselves to be robbed" and "Resignation," demonstrators demanded the government revise the draft or step down. In front of the Parliament, banners were displayed reading "Generation Z is Coming" and "Young Bulgaria Without the Mafia."

Organizers urged demonstrators to keep the protest peaceful, warning that provocations were possible and calling on anyone witnessing such acts to record them.

Later, however, tensions escalated as small groups of protesters moved to the offices of the main ruling parties and started throwing plastic and glass bottles, firecrackers, stones at the buildings and police officers guarding them.

Clashes erupted between police officers and youths dressed in black hoodies and masks, while garbage containers were burned and police vehicles were vandalized. Police in full riot gear pepper-sprayed protesters.

Emergency services reported that several injured people were taken to hospitals, while many were examined and provided with assistance on the spot. Police said that 10 people were detained.

Opponents of the proposed budget have argued that the plan to increase spending would have been financed primarily through higher taxes on businesses and workers, as well as a sharp rise in public debt. They argued this would spur inflation without improving the efficiency of public services.

The government has argued that its draft budget is necessary to meet the Eurozone's requirement for a budget deficit under 3 percent of GDP.