* Putin wants access for experts at crash site
* Says crash should not be used for political ends (Adds Putin quotes, background)
MOSCOW, July 21 (Reuters) - Russian President Vladimir Putin said on Monday the downing of a Malaysian airliner in east Ukraine must not be used for political ends and urged separatists to allow international experts access to the crash site.
"Everything must be done to guarantee the security of international experts at the site of the tragedy," Putin, wearing a dark suit and tie, said in an unusual televised address standing alone by a desk in an office.
Putin, who looked drawn, reiterated his belief that the incident would not have happened if Ukrainian government forces had not ended a truce and resumed a military campaign against the pro-Russian rebellion in eastern Ukraine.
"However, nobody should - and no one has the right to - use this tragedy to achieve selfish political ends. Such events should not divide people but unite them," he said.
Putin's comments, following a flurry of telephone diplomacy, appeared aimed at countering criticism by Western leaders who accused him of doing little to persuade separatists whom they believe shot down the airliner to stop fighting.
Putin defended his role in the crisis and reiterated calls for an end to hostilities in eastern Ukraine.
"We have more than once called on all sides in the conflict to immediately stop the bloodshed and begin negotiations," he said.
He called for a "humanitarian corridor" to allow experts access to the site where the airliner was brought down, killing all 298 people on board, in rebel-controlled territory but stopped short of issuing a public appeal to the separatists.
U.S. and European leaders, who have imposed sanctions on Moscow over its annexation of Ukraine's Crimea peninsula and its role in the east, say weapons and fighters flowing across Russia's border into Ukraine are fueling the violence.
Criticism of Russia's role has turned to anger in Western capitals over gruesome accounts of bodies and evidence being manhandled by fighters and residents.
Despite calls for an end to fighting, clashes broke on Monday out in the rebel stronghold of Donetsk near a railway station, with artillery fire sending plumes of smoke skywards in what separatists said was an attempt by government forces to enter the city they seized in April. (Writing by Alissa de Carbonnel Editing by Timothy Heritage)