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Hong Kong CNN  — 

Protesters set fire to the entrance of Hong Kong’s Polytechnic University early Monday in a last ditch attempt to stop riot police from entering, as the siege of the heavily fortified campus entered its second day.

The flames followed a night of violence as students hurled petrol bombs at Hong Kong police, who deployed water cannons and warned that if given no other choice they would use “live rounds.”

Around 8 a.m. on Monday, dozens of protesters attempted to leave the university through the main entrance as police fired rounds of tear gas. CNN witnessed multiple protesters being led away by police on the roads leading from the campus.

The Hong Kong police force has yet to disclose how many people have been arrested in the almost 24-hour siege, and there are no clear numbers for those who have been injured.

As of Monday morning, several hundred protesters were thought to remain barricaded inside the university’s main building.

Over the weekend, the site had been used to stockpile weapons, including bows and arrows, catapults and petrol bombs, though it was unclear how many weapons remained.