US President Obama embarks on Asian tour

     The US leader will visit Japan, South Korea, Malaysia and the Philippines.The White House says the trip will focus on closer economic ties, but regional security - including China's increasingly powerful presence - is likely to dominate talks. Asian allies are concerned over the US ability to focus on the region amid competing priorities, say analysts.The trip was an opportunity to reinforce the importance the US placed on Asia and to re-establish ties at the leadership level, former US Assistant Secretary of State PJ Crowley told the BBC.
     "Many traditional allies... [also] value a strong US presence in the region to balance against an assertive China," Mr Crowley said. Mr Obama's visit comes amid a "period of very significant tension among American allies, and between American allies and China", he added.