BAGHDAD , Iraq ( CNN ) -- A U.S. military helicopter crashed in southern Iraq early Thursday morning , killing all seven U.S. soldiers on board , the military said . A U.S. Chinook helicopter , similar to this British Chinook , crashed in Iraq , the U.S. military said . Officials have not determined the cause of the crash , but do not suspect hostile activity . `` Based on our initial reports , it is accurate to characterize this as an accident , '' said Maj. John Hall , a U.S. military spokesman . The CH-47 Chinook was part of a four-aircraft convoy that was flying from Kuwait to Balad in northern Iraq . The chopper went down about 62 miles ( 100 km ) west of Basra . The other helicopters in the convoy did not sustain damage , Hall said . The names of the soldiers were not released pending notification of next of kin . The CH-47 Chinook is primarily used for transporting troops , supplies and artillery . Meanwhile , two parked car bombs detonated in western Baghdad Wednesday in quick succession , killing eight people and wounding 25 , an Interior Ministry official said . Baghdad was also struck by a series of roadside bombings that killed two and wounded 16 , the official said . The bombs detonated in two cars parked near each other outside a hospital in Harthiya district shortly before noon ( 0900 GMT ) , the official said . It was the second twin car bomb attack in Baghdad this week . On Monday , two car bombs detonated in central Baghdad , killing 12 and wounding 37 . Five roadside bombs struck the Iraqi capital on Wednesday , one of which targeted the head of New Baghdad 's district council , the official said . The council leader 's driver was killed , while he and his security guard were wounded in the attack . Another roadside bomb in eastern Baghdad killed an Iraqi policeman and wounded five other people . Two other roadside bombings in the Iraqi capital wounded nine Iraqi soldiers and civilians . Elsewhere on Wednesday , an assistant to the governor of Nineveh province was gunned down as he was leaving evening prayers in central Mosul , city police said . Shamel Younis was walking outside the mosque when gunmen in a car shot and killed him , then fled the scene . The new U.S. commander in Iraq said Tuesday that security in the country has improved , but is still in a `` fragile state . '' `` As we 've said many times , everyone is encouraged by the progress that has been made here in Iraq , but we still have a lot of work to do , '' said Gen. Ray Odierno , who took command of U.S. forces in Iraq on Tuesday . Watch change of command ceremony » . Odierno replaced Gen. David Petraeus , whose tenure saw a reversal in the country 's rising violence . `` It 's a proud moment for me to be given the responsibility to take command of Multi-National Force-Iraq and continue the mission here in Iraq as we move forward , '' Odierno said in Tuesday 's handover ceremony in Baghdad , which was attended by Defense Secretary Robert Gates . `` We are in a fragile state now . What I want to do is build it to a more stable state . And I think we 're in the process of doing it . It just takes some time , and it 's slow , '' Odierno said . Odierno said he is `` encouraged '' by the growth of Iraqi security forces and the national police . `` We 're starting to see signs of some other of the governmental capacities begin to grow , which I think is extremely important , '' he said . CNN 's Jomana Karadsheh and Cal Perry contributed to this report .
NEW : Military spokesman characterizes initial reports point to an accident . NEW : Other choppers in the convoy did not sustain damage , spokesman says . Baghdad military : CH-47 Chinook helicopter crashed 100 km ( 62 miles ) west of Basra . Twin car bombs outside Baghdad hospital kill 25 , injure eight .