LONDON (AP) — British Foreign Secretary Boris Johnson is urging North Korea to "change course" and engage in diplomacy to resolve the crisis over its nuclear ambitions. But he says U.S. President Donald Trump is right to keep the option of military action open.

In a speech in London Monday, Johnson said the U.S. has rightly offered "sensible reassurances" to Pyongyang that it does not seek regime change or invasion. But he said Trump has an "absolute duty to prepare any action" to keep America and allies safe.

Johnson says the Iranian nuclear deal is evidence diplomacy can work and that he is confident that deal will survive, despite Trump's opposition.

Urging more work to curb nuclear proliferation, he says the alternative is "a nuclear version of the final scene of 'Reservoir Dogs.'"