China has accused Hong Kong democracy activists of trying to start a revolution as it warned some campaigning for recent primaries may have breached a tough new security law it imposed on the city. The bellicose comments by the Liaison Office, which represents China's government in the semi-autonomous city, dramatically heighten the risk of prosecution for opposition parties and leading figures. More than 600,000 Hong Kongers turned out over the weekend to choose candidates for upcoming legislative elections despite warnings from government officials that the exercise could breach Beijing's sweeping new law. Polls for the city's partially elected legislature are due to take place in September. Pro-democracy parties are keen to use seething public anger towards Beijing's increasingly authoritarian rule to win a majority within a chamber that has always been weighted in favour of pro-establishment parties. Control could give them a greater ability to stall budgets and legislation, one of the few tactics left open to the opposition camp. But in a statement released late Monday, the Liaison Office described the primaries as "a serious provocation against the current election system". It said campaigning that pushed to take control of and paralyse the chamber is a breach of Article 22 of the security law. Article 22 targets "subverting state power". It outlaws "serious interference and obstruction" of the central and Hong Kong governments, or any act that causes them to be "unable to perform their functions normally". - 'Colour revolution' - The Liaison Office's statement also singled out Benny Tai, a prominent democracy activist who played a leading role in organising the primary. "The goal of the Benny Tai gang and the opposition camp is to seize power to govern Hong Kong, with a vain attempt to launch a Hong Kong version of a 'colour revolution'," the office said. Colour revolution is a term used to describe multiple popular protest movements around the world that either swept a government from power or tried to. However in authoritarian Communist China -- itself a state built from revolution -- the term has frequently been used by both the government and state media to describe an illegitimate revolution backed by hidden, usually western, forces. Tai, a law professor, has previously been jailed for his involvement in peaceful pro-democracy protests in 2014. On Tuesday, the Apple Daily newspaper published a column by Tai in which he hailed the primaries. "Threats from the powerful did not deter tens of thousands of citizens from coming out and casting a ballot," he wrote. "They have not given up on their determination to pursue democracy and universal suffrage." Apple Daily is owned by Jimmy Lai, one of the few tycoons in Hong Kong to openly support democracy. He is also being prosecuted for taking part in pro-democracy protests. US Secretary of State Mike Pompeo meanwhile sent his congratulations "to Hong Kong's pan-democrats for a successful primary" in a Twitter post calling for the Legislative Council's September elections to be "equally free and fair." - Fear grips city - Hong Kong has seen waves of pro-democracy demonstrations over the last decade. But last year the city was convulsed by seven straight months of huge and often violent protests. In response, Beijing imposed its security law in a bid to end the unrest once and for all. The legislation bypassed Hong Kong's legislature and its contents were kept secret until the law was enacted at the end of last month. It targets subversion, sedition, terrorism and foreign collusion with penalties of up to life in prison. But its broad phrasing -- such as a ban on encouraging hatred of China's government -- has sent fear rippling through a city used to speaking its mind. Beijing now claims jurisdiction over some serious cases and has allowed its intelligence apparatus to set up shop openly in the territory for the first time. Those provisions have ended the legal firewall that existed between the Chinese mainland's Communist Party-controlled courts and Hong Kong's independent judiciary. National security laws are routinely used on the mainland to crush dissent. China says the Hong Kong legislation is needed to return stability after last year's protests, which it has portrayed as a foreign plot to destabilise the motherland. Opponents, including many Western nations, say the law has started to demolish the "One Country, Two Systems" model where China agreed to let the city retain key civil liberties, as well as legislative and judicial autonomy, until 2047.