A bomb blast in Sanaa kills at least three people as Shi'ites mark Ashura for the first time in Yemen.<br/> <br />No one is claiming responsibility for the attack.<br/> <br />(SOUNDBITE) (Arabic) WITNESS ABDULRAB AL-MORTATHA, SAYING:<br/> <br />"There are no details on the numbers of wounded because they have been taken to many different hospitals. This was a terrible crime."<br/> <br />The United States, wary of the threat to neighboring top oil producer Saudi Arabia has stepped up drone strikes on suspected militant positions in Yemen.
