Beijing has responded with defiance to international criticism of its Hong Kong national security law, threatening countermeasures against the UK and the US and describing Washington’s efforts to raise the issue at the UN security council as “pointless”. One day after Beijing’s legislature approved plans to move ahead with sweeping anti-sedition legislation in Hong Kong, foreign ministry spokesman Zhao Lijian warned countries that Hong Kong is “purely an internal Chinese matter” and that “no other country has the right to interfere”. In response to the vote, the British foreign secretary, Dominic Raab, said the UK would extend the rights of up to 300,000 British national overseas passport holders in Hong Kong if China persisted with the law. Zhao said that if the UK “insists on unilaterally changing its practices” it will be in violation of international law and norms. “We firmly oppose this and reserve the right to take countermeasures,” he told a regular press briefing in Beijing. China’s plan has prompted international condemnation, most vehemently from the US, which has asked the UN security council to hold a meeting on the issue. Zhao said: “We urge the US to immediately stop such pointless political manipulation and do something useful for the international community.” China has said the legislation – aimed at criminalising separatism, subversion, terrorism and foreign interference – is necessary in the face of increasingly volatile protests that have rocked Hong Kong for the past year. But many say the laws will be used to target critics of the government, and threaten civil liberties as well as the city’s autonomy. The legislation is also expected to enable Beijing to establish intelligence agencies in Hong Kong, including a domestic intelligence agency potentially involving the ministry of public security (MPS) and the ministry of state security, China’s main intelligence agency. Late on Thursday, the MPS said it would use “all efforts to guide and support the Hong Kong police to stop violence and restore order”. Hong Kong’s police force is independent from China and the MPS has no enforcement powers in the former British colony. Beijing’s defence of its plans came as the Hong Kong government warned Washington to stay out of its internal affairs. The US has signalled its intention to revoke Hong Kong’s special trade and economic status, under which the city is treated as separate from China on terms that have underpinned Hong Kong as a global financial hub. The US president, Donald Trump, was due to announce his response later on Friday. Trump’s top economic adviser, Larry Kudlow, has said Hong Kong may now need to be treated like China on trade and other financial matters. The Hong Kong government said: “Any sanctions are a double-edged sword that will not only harm the interests of Hong Kong but also significantly those of the US.” It added that from 2009 to 2018, the US trade surplus with Hong Kong was the biggest among all its trading partners, totalling $297bn of merchandise, and 1,300 US firms are based in the city. In a separate statement published in several local newspapers, Hong Kong’s leader, Carrie Lam, urged “fellow citizens” to “join hands to pursue our dreams while putting aside our differences”. She said the legislation was needed because of a “terrorist threat” and because organisations advocating “independence and self-determination” have challenged the authority of Beijing and local governments and pleaded for foreign interference. The plan ignited the first big protests in Hong Kong for months, with thousands of people taking to the streets, prompting police to fire pepper pellets to disperse crowds in the heart of the city’s financial district. The five demands of last year’s pro-democracy protest movement included universal suffrage and an independent inquiry into police handling of the protests, but not independence. A minority of protesters waved “Hong Kong independence” flags. China has said it will not tolerate calls for independence, which Beijing has called its “red line”. On Friday dozens of people protested in a mall in Hong Kong’s Central district, chanting slogans in the main atrium and draping banners over the balconies. Police waited in vans parked prominently outside but did not attempt to break up the gathering. The security legislation, along with a bill to criminalise disrespect for China’s national anthem, is seen by protesters as the latest attempt by Beijing to tighten its control on the city. European Union governments echoed criticism of the law by Australia, Canada, the UK and US on Friday, expressing their “grave concern”, the EU’s top diplomat Josep Borrell said following a video meeting of the bloc’s 27 foreign ministers. “We believe that this seriously risks undermining the one country, two systems principle,” Borrell said, referring to Hong Kong’s autonomy. “Our relationship with China is based on mutual respect and trust but this decision calls this into question.” On Friday, Chinese state media lauded the decision in the National People’s Congress. An editorial from the Xinhua news agency said: “Safeguarding national security means safeguarding the ‘one country, two systems’.” The editorial, defending China’s right to institute the law, warned all anti-China forces in Hong Kong to “immediately stop illegal and criminal acts” that endanger national security. “Do not continue misjudging the situation and never underestimate the Chinese government and the will of the Chinese people.” The People’s Daily called the NPC approval of the plan the “resolute expression of 1.4 billion Chinese people”. “It sends a strong signal … to anti-China forces in Hong Kong desperately fighting like a cornered wild beast: your defeat has already been decided.” Beijing also spoke out on Friday against Taiwan, which has promised to help fleeing Hongkongers, exacerbating tensions between the rival governments. China warned it would use all means to prevent pro-independence forces separating Taiwan from China. Li Zhanshu, the head of China’s parliament, said non-peaceful action against the Chinese-claimed island would be a last resort.