"I've signed an executive order that authorises new sanctions against the Syrian government and Iran and those that abet them for using technologies to monitor and track and target citizens for violence. These technologies should be in place to empower citizens, not to repress them."

The United Nations Secretary General Ban Ki-moon has condemned the bombing by Sudanese warplanes of a market in South Sudan and called on the government in Khartoum to stop the fighting. Earlier, the UN special representative in South Sudan said observers were needed urgently to monitor fighting on the frontier between the two countries. But the Sudanese President Omar al-Bashir has ruled out negotiations with South Sudan. He was speaking during a visit to the oil field and border town of Heglig, which was occupied by South Sudanese troops nearly two weeks ago.

A Royal Navy inquiry has found that a British nuclear-powered submarine ran aground off the coast of Scotland because of a series of errors. HMS Astute, one of the most expensive and advanced vessels in the service, was marooned for 10 hours near the Isle of Skye. Jonathan Beale reports.

The official inquiry into the incident in October 2010 highlights a catalogue of errors: there was no dedicated plan or briefing before the manoeuvre; navigation charts had not been properly plotted; there were also faults with the equipment on board. As she was left with more than ￡80,000 of damage to its steering mechanism, more damage was caused when it was hit by a tug that came to its rescue. The Royal Navy says it's now made a number of recommendations to make sure it doesn't happen again.