China has warned Britain, the United States and the rest of the NATO alliance that it will not “sit by and do nothing” if challenges approach.

A senior diplomat also accused the 30 allies of slander after they agreed for the first time that Beijing posed “systemic challenges” to international rules and values.

At a summit on Monday in Brussels, the alliance expressed concern about what it called China’s “coercive policies”, how the country is rapidly expanding its nuclear arsenal with more warheads and its military cooperation with Russia.

A spokesperson for the Chinese Mission to the European Union, responding to the comments, called on NATO to be more rational about China and “stop hyping up in any forum the so-called ‘China threat'”.

Please use Chrome browser for a more accessible video player

Prime Minister Boris Johnson spoke ahead of the NATO summit

The allies had stressed they did not view China as a threat but a challenge.

Still, they only mentioned China in relatively mild terms for the first time in 2019. The language used in a communique released after their gathering in the Belgian capital on Monday was a lot stronger.

The Chinese spokesperson said: “NATO is slandering China’s peaceful development and misjudging the international situation and its own role. It represents a continuation of the Cold War mentality and bloc politics”.

More on China

The spokesperson said China’s defence policy is “defensive in nature”, claiming that the military budget is just a fraction of total military expenditure by the alliance – $209bn compared with a collective sum of $1.12trn.

“We will follow very closely NATO’s strategic adjustment and its policy adjustment towards China. China will not present ‘systemic challenges’ to anyone, but we will not sit by and do nothing if ‘systemic challenges’ come closer to us,” the spokesperson said in a statement.

The remarks come after China earlier accused the G7 of slander and “political manipulation” after the group of industrialised nations criticised Beijing following a summit in Cornwall.