New York  - UN Secretary General Ban Ki-moon on Wednesday named Peter W Galbraith, a US expert on arms control, as deputy chief of the United Nations mission in Afghanistan.

Galbraith will replace Christopher Alexander of Canada to work in war-torn Afghanistan, where NATO and non-NATO countries maintain 55,000 military personnel and the US has more than 10,000 troops to fight terrorism, the Taliban and al-Qaeda.

Washington  - Discovery astronauts were preparing to undock from the space station later Wednesday to head back to Earth after completing a milestone mission that has doubled the station's capacity.

The mission astronauts installed the fourth and final set of solar panels needed to double power capacity at the station so it can hold six instead of the current three long-term residents - possibly as early as May.

Washington  - US President Barack Obama said Wednesday he backs the expansion of NATO to European countries aspiring to join the alliance but pledged to work towards reinvigorating US-Russian relations.

Obama, meeting with NATO Secretary General Jaap de Hoop Scheffer just a week before the alliance summit, also said he will present his administration's strategic review of the situation in Afghanistan to other members.

Washington - US Treasury Secretary Timothy Geithner sent the US currency tumbling Wednesday by saying he was open to enlarging the International Monetary Fund's currency reserves, but rallied again as he clarified the dollar will remain "the world's dominant reserve currency."

His comments at the Council on Foreign Relations in New York were in response to China's suggestion that a new global currency reserve replace the dollar in order to guard against fluctuations in economic crises.

Washington  - US President Barack Obama said Wednesday he backs the expansion of NATO to European countries aspiring to join the alliance but pledged to work towards reinvigorating US-Russian relations.

Obama, meeting with NATO Secretary General Jaap De Hoop Scheffer just a week before the alliance summit in Germany and France, also said he will present his administration's strategic review of the mission in Afghanistan to other members.

"We expect to share that with our NATO counterparts," Obama said.

Washington - US President Barack Obama will name a task force to overhaul the country's 96-year-old tax code and plug loopholes that could save 300 billion dollars per year, Obama's top budget advisor said Wednesday.

The task force will be headed by former Federal Reserve chairman Paul Volcker and directed by Austin Goolsbee, a close economic advisor of Obama's, and should report back by December 4.