SOFIA, BULGARIA (BLOOMBERG) - Thousands of Bulgarians demonstrated at the country's Parliament, renewing calls for the resignation of Prime Minister Boyko Borissov.

Continuous anti-government rallies against Mr Borissov over his failure to fight rampant corruption have deepened a political crisis that has raged since July, when activists called for the Premier and Chief Prosecutor Ivan Geshev to resign.

They've both been accused of harbouring links with organised crime, which they deny.

Hundreds of police officers guarded Parliament in central Sofia on Wednesday. Protesters shouting "Resignation!" threw apples and eggs as they tried to break through the cordon.

Police used pepper spray to disperse the crowd after more than 20 police officers were injured from an unknown gas substance, Mr Ivan Georgiev, a director at the security police department in Sofia, told reporters. At least two people were detained.

"There's no other way out of the blockade of the state except for a peaceful, normal political act of resignation when there's no trust," President Rumen Radev, who has repeatedly criticised the government and the chief prosecutor, told lawmakers.

These resignations "are unavoidable".

Mr Borissov is proposing to rewrite Bulgaria's constitution, saying it will bolster judicial independence and has also suggested he may quit.

This week, he's trying to win the support of half of lawmakers required to start a lengthy parliamentary procedure and has said he'll step aside once a special assembly is approved to edit the law - in November at the earliest.

Bulgaria has been repeatedly criticised by European Union institutions for its insufficient rule of law, and ranks the worst in the bloc in Transparency International's Corruption Perceptions Index.