Former Japanese prime minister Shinzo Abe will be remembered for his “global leadership through unchartered times” following his “incredibly sad” death, Boris Johnson has said.
Mr Abe, 67, was shot from behind during a campaign speech in western Japan on Friday and later died in hospital.
The shooting prompted shock and sadness among British politicians as the news emerged on Friday morning.
Mr Johnson tweeted: “Incredibly sad news about Shinzo Abe.
“His global leadership through unchartered times will be remembered by many. My thoughts are with his family, friends and the Japanese people.
“The UK stands with you at this dark and sad time.”
Chancellor Nadhim Zahawi said the news was “heart-breaking”.
“We enter politics to serve and to try and make the world a better place,” he tweeted.
“Shinzo Abe has lost his life in pursuit of that noble aim. May he rest in eternal peace.”
Before his death was confirmed, Foreign Secretary Liz Truss said she was “devastated” by the shooting.
She tweeted: “Devastated to hear about the attack on former Prime Minister Abe. We stand with our Japanese friends at this difficult time.
“Our thoughts and prayers are with his family and friends.”
Mr Abe was Japan’s longest-serving leader before stepping down for health reasons in 2020.
Police arrested the suspected gunman at the scene of the attack, which shocked people in a country known as one of the world’s safest.
Labour leader Sir Keir Starmer had earlier called it a “dark day”.
He tweeted: “Our hearts are with the family of Shinzo Abe and the Japanese people.
“A truly dark day.”