Clashes broke out between police and protesters in Hong Kong last night, during a protest against Beijing's move to intervene in an oath-taking controversy involving two pro-independence Hong Kong lawmakers.

Police officers used pepper spray to drive back protesters, some of whom hurled plastic bottles at them outside the Chinese liaison office in Hong Kong on the eve of a controversial ruling by Beijing which is expected to bar the two lawmakers from Hong Kong's Legislative Council (Legco).

As of 10pm, at least four groups of protesters were still in stand-offs with police officers clad in riot gear near the Chinese liaison office. Ignoring calls to disperse and threatening to stay there all night, protesters opened up umbrellas and occupied tram tracks over an area extending over three tram stops.

Young men in hoodies and black masks were also seen carrying dustbins and looking for heavy objects in scenes reminiscent of a riot in Mongkok in February this year.

Some 4,000 protesters marched to the Chinese liaison office last night, Hong Kong's South China Morning Post said in an online report. Earlier in the day, over 13,000 protesters, many in black, marched from Wan Chai district towards the Court of Final Appeal in Central, before diverting their route to head to the Chinese liaison office in Sai Wan.

Traffic came to a standstill as the crowd forced its way to the office. Scuffles broke out between protesters and police along the way as protesters demanded that police open more sections of the road. A double-decker bus even had to reverse as the crowd charged forward.

Mr Kevin Lee, 28, an IT analyst who joined the protest march, said: "Those two lawmakers were democratically elected. It's for Hong Kongers to decide if we want them as lawmakers. Beijing said they have their bottom line, so do we."

The National People's Congress Standing Committee in Beijing is expected to hand down a ruling today that bars lawmakers Sixtus Leung, 30, and Yau Wai Ching, 25, from retaking oaths to take their seats in the city's legislature. The duo from localist political party Youngspiration were elected in September and had their swearing-in oaths invalidated on Oct 12 for using words that insulted China. They were then banned from entering the legislature.

Beijing's move - the fifth time it is handing down its interpretation of the Basic Law, or Hong Kong's mini-Constitution - has sparked wide concerns that China is tightening its grip on the city.

While Hong Kong is part of China, it was granted a high degree of autonomy under the "one country, two systems" framework after it was handed back to China in 1997.

While Legco president Andrew Leung allowed the two lawmakers to retake their oaths, his decision was legally challenged by Hong Kong Chief Executive Leung Chun Ying.

On Nov 3, the case was heard in the Hong Kong High Court, with the duo's lawyers arguing that the dispute should be dealt with within the legislature. But even before the court could issue a ruling, Beijing announced last Friday that it was weighing in on the controversy by interpreting the Basic Law.

This would undermine the city's judicial independence, warned lawyers who will hold a silent protest march tomorrow.

But Beijing said Mr Sixtus Leung and Ms Yau have "hit the bottom line of the 'one country, two systems' principle and posed a grave threat to national sovereignty and security", in a statement on Saturday, reported Xinhua news agency.

China's national television on Saturday said Beijing may set out the "format and conduct" for lawmakers to take their oaths and criteria for disqualification.

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