Prime Minister Theresa May has said the UK will “redouble” its efforts to curb North Korea’s “outrageous” weapons testing regime, but urged China to exert its influence over Pyongyang.
Speaking as she travelled to Japan for a visit, she accused North Korea of “significant actions of provocation”.
Japan is preoccupied with tackling the fallout from North Korea’s missile test over its northern Hokkaido island.
The PM’s official visit also aims to drum up trade and allay Brexit worries.
Arriving in Kyoto shortly before 14:00 local time, Mrs May insisted North Korea’s weapons testing programme was illegal.
She said: “We will be re-doubling our efforts with our international partners to put pressure on North Korea to stop these illegal activities.”
The PM said the UK was involved in “discussions about further sanctions” and looking at “the sort of change that China can bring”.
She said China had “a key role to play” and urged Beijing to do “everything it can” to exert pressure on North Korea.
Japan’s Prime Minister Shinzo Abe called the missile launch an “unprecedented” threat to his country, while US President Donald Trump said it was an act of “contempt”.
Mr Abe and Japan’s Emperor Akihito are expected to greet Mrs May when she arrives in Tokyo for the three-day trip.
The PM is accompanied on the trip by International Trade Secretary Liam Fox and a delegation of business leaders drawn from a range of sectors.
They will be keen to demonstrate their enthusiasm for new trade agreements with Japan.
The UK will, however, be unable to sign any bilateral deals until it has left the EU in 2019.
Japan, which is currently negotiating a trade deal of its own with the EU, has been forthright in expressing concerns about Brexit’s impact on its UK-based firms, which employ about 140,000 people.
Mr Abe will be seeking assurances from Theresa May that Brexit will not be detrimental to Japanese businesses with bases in the UK.
Japan also wants to know what kind of relationship the UK will have with the EU post-Brexit.
That is the subject of ongoing negotiations in Brussels between Brexit Secretary David Davis and the EU’s chief negotiator Michel Barnier. Mr Barnier has urged the UK to start “negotiating seriously”.
In a report last year, the Japanese foreign minister warned Brexit could result in Japanese firms moving their European head offices out of Britain.
It urged the British government to deal with concerns in a “responsible manner”.
Nomura bank, Hitachi and carmakers Honda, Nissan and Toyota all have bases in the UK.
Earlier this year, Nissan said it would build two new models – the new Qashqai and X-Trail – at its Sunderland plant after the government promised that competitiveness would not be damaged by its EU exit.