Obama in Berlin looks to restore transatlantic ties

US presidential hopeful Barack Obama on Thursday kicked off a European tour in Berlin, saying he aimed to give a fresh start to transatlantic ties, from the city where the Cold War was won.

Obama, who arrived from Israel, met first with German Chancellor Angela Merkel while a crowd of supporters cheered and snapped pictures outside.

The Illinois senator was also to see Foreign Minister Frank-Walter Steinmeier and Berlin Mayor Klaus Wowereit before making a foreign policy speech in front of an expected crowd of tens of thousands.

The presumptive Democratic candidate said he wanted the United States and Europe to rediscover their common ground.

"There is no doubt that part of what I want to communicate on both sides of the Atlantic is the enormous potential of us restoring a sense of coming together," he told reporters traveling with him.

Obama defended himself against claims he is defying convention by electioneering abroad, saying he wanted to speak to the whole of Europe so he needed a big venue. He said it was Berlin's symbolism that drew him here first.