Barack Obama has launched an aggressive defence of the landmark Iranian nuclear deal, rejecting the idea that it leaves Tehran on the brink of a bomb and arguing the only alternative to the diplomatic accord is war.

Iran’s top leader yesterday stopped short of giving his endorsement to the framework nuclear deal struck last week between Tehran and world powers, while the country’s president warned separately that Tehran’s approval of a final deal depends on the immediate lifting of all sanctions related to its controversial nuclear programme.

Critics believe Iran will use the deal to boost its economy while continuing to try to build a bomb, but the agreement may be the best global powers could get, writes Dan Perry