BBC News with Marion Marshall

At a time of budget austerity, President Obama has unveiled a revised defence strategy, which he says would cut US military spending by $450bn over 10 years. He insisted the United States would maintain its military superiority. Our security correspondent Gordon Corera has the details.

President Obama made clear that the current tide of war was

receding

and this was the moment to decide what comes next. He may have ended his announcement by reminding people that even after proposed reductions, the US military budget will still be larger than the next 10 countries combined, but there was more than

belt-tightening

to this exercise. A move to a smaller army is part of the shift away from the kind of manpower-intensive counter-insurgency and nation-building campaigns that define the long wars in Iraq and Afghanistan.

A series of bomb attacks in Iraq targeting Shia Muslims has killed at least 73 people. In the worst violence, a suicide attack on Shia

pilgrims

in Nasiriyah killed at least 44. That attack came just hours after a number of bombs in Baghdad killed at least 29 people. Rafid Jabboori reports.

The attacks struck Shia areas in southern Iraq and Baghdad, and left dozens dead and injured. Car and roadside bombs were used. According to the Iraqi Ministry of Interior, the targets were all civilian[s]. The deadliest explosion hit Shia pilgrims who were passing through a police checkpoint near the southern city of Nasiriyah. Although there was no immediate claim of responsibility, (but) Shia pilgrims and the police have been frequently targeted by al-Qaeda in Iraq, a Sunni extremist group.