The United States was catapulted into a worldwide diplomatic crisis today, with the leaking to the Guardian and other international media of more than 250,000 classified cables from its embassies, many sent as recently as February this year.

At the start of a series of daily extracts from the US embassy cables – many designated ‘secret’ – the Guardian can disclose that Arab leaders are privately urging an air strike on Iran and that US officials have been instructed to spy on the UN leadership.

These two revelations alone would be likely to reverberate around the world. But the secret dispatches, which were obtained by WikiLeaks, the whistleblowers’ website, also reveal Washington’s evaluation of many other highly sensitive international issues.

These include a shift in relations between China and North Korea, high-level concerns over Pakistan’s growing instability, and details of clandestine US efforts to combat al-Qaida in Yemen.

Among scores of disclosures that are likely to cause uproar, the cables detail: