Relations between the US and China are already fraught, but now a move by Donald Trump has heightened tensions.
He has signed into law a bill that supports pro-democracy protesters in Hong Kong.
It comes after nearly six months of protests in the region, which began over a proposed law to allow extradition to mainland China.
The protests have since snowballed into a larger pro-democracy movement.
The bill signed by Trump has the potential to tighten restrictions on trade agreements between the US and Hong Kong, in a move that has exacerbated already tense relations with China.
What changes could the act bring?
The bill will amend a 1992 policy act, which outlines the US foreign policy in relation to Hong Kong. In 1997, when the one-country-two-systems policy was enacted, the US put forward a provision that allowed special trading relationships with the Hong Kong Administrative Council. It is this agreement that may be restricted, with those trade agreements dependent on the continuation of Hong Kong's autonomy.
Annually, US officials will assess whether Hong Kong is retaining its autonomy and certify whether the administration should retain its trading relationship. The act also allows the US to sanction officials who they say are responsible for human rights violations.
How has China responded?
Over the past few months, Chinese officials have been using Western social media channels to counter what they say is "Western misunderstanding". Upon the signing of the act, Twitter was flooded with sharp reactions from Chinese officials.
Via Twitter, the Foreign Ministry claimed that the act was a "severe interference in Hong Kong Affairs" whilst adding that "the US disregarded facts and distorted truth" by backing "violent criminals". " The egregious & malicious nature of its intentions is fully revealed," Lijian Zhao continued.
How have the protestors responded?
Shortly after the Act was signed, protestors took to Edinburgh Place, in Central for the "Thank You and March On" demonstration, aimed at thanking the US government. Protestors waved US flags while others held posters of the US president.
High profile demonstrators had travelled to the US earlier this year seeking international support, including Joshua Wong who said via Twitter that the Bill signifies a "fundamental change" to US-China relations.
Click on the player above as Seana Davis in The Cube explains more.