Britain and Japan will work together on stepping up the pace of sanctions against nuclear-armed North Korea after its "outrageous" firing of a missile over Japan, British Prime Minister Theresa May said Thursday.

"In response to this illegal action, Prime Minister (Shinzo) Abe and I had agreed to work together and with others in the international community to strengthen pressure against North Korea including by increasing the pace of sanctions" against Pyongyang, May said during an official visit to Japan