Hong Kong police on Thursday entered the Polytechnic University campus, which had been under siege for 11 days of clashes with hundreds of students, to check that there was no one left inside and remove any dangerous items.

The police move into the Polytechnic University came after its administration said that they believed no one else remained inside after a two-day search ended Wednesday.

Faculty teams found only a young woman in a weak condition and a stockpile of dangerous items including petrol bomb and corrosive liquid.

Senior police officer Chow Yat Ming said the focus of the operation is not to arrest any holdouts but on removing hazardous items that are a threat to public safety, and to gather evidence of “malicious” damage to campus facilities.

The campus has become one of the iconic sites of the pro-democracy demonstrations being carried out by thousands of people in the city for months and was turned into a battleground.

Walls painted with phrases such as “Free Hong Kong,” remnants of fires, barricades made from furniture, a trail of Molotov cocktails, masks and helmets, and student slippers and backpacks are all now found on the campus.

More than 5,000 people have been detained since the unrest started in June over a China extradition bill that was seen as an erosion of freedoms promised when the former British colony returned to Chinese control in 1997. The movement has since expanded into wider demands, including universal suffrage and an independent investigation of police conduct.

The protest movement was given another fillip after President Donald Trump signed two bills to support Hong Kong human rights and pro-democracy activists. China immediately warned it would take strong countermeasures.

On Tuesday, Hong Kong Carrie Lam said that the city’s Special Administrative Region (HKSAR) government will stick to the “one country, two systems” principle and safeguard Hong Kong residents’ human rights and freedom protected under the Basic Law.

Last week, the city’s police asked the demonstrators to leave the city’s Polytechnic University (PolyU) campus as soon as possible, citing bad and dangerous conditions inside.

The protests, which have been drawing massive crowds since June following a contentious proposed extradition law that has been pulled by the government, have mutated into a movement that seeks to improve the democratic mechanisms that govern Hong Kong and safeguard – or expand – the region’s partial autonomy from Beijing.

The controversial China extradition bill was withdrawn in early September but the movement has morphed into a wider campaign for greater democracy and against alleged police brutality.