WASHINGTON — The United States has a long way to go before Russia overcomes deeply entrenched skepticism of its missile defense plans, but that does not threaten efforts to "reset" relations, a Pentagon official said Wednesday. 


Moscow has repeatedly demanded clarification from Washington as U.S. missile defense plans in Europe take shape, voicing surprise at Romania's offer this month to host interceptor missiles. 


News that Bulgaria expressed a willingness to also play a role further raised alarms. 


Alexander Vershbow, assistant defense secretary for international security affairs and former U.S. ambassador to Moscow, said Washington had not asked Bulgaria to host any missile shield elements so far. He added that Moscow knew last year that Romania was a possible site. 


"So we don't believe that this was as big a surprise as it has sometimes been portrayed," he said. 


Vershbow said Washington would continue to "lay down the facts" to convince Moscow that its missile defense plans were not aimed at Russia and instead focused on countries like Iran. 
"We still have a long way to go. Skepticism in Russia is still deeply entrenched. And we've seen it in public statements in recent weeks. But we'll continue to engage," he said. 


Asked what the United States might be able to do differently to assuage Russia, Vershbow said: "I don't think we have any new techniques. We will continue to engage, lay down the facts, try to address the Russian arguments on a substantive basis." 


U.S. President Barack Obama rolled out a revised European missile defense strategy in September that focuses more on Iranian short- and medium-range missiles. U.S. officials have expressed hope that Russia might eventually play a role in the strategy. 
Russia's most powerful politician, Prime Minister Vladimir Putin, and other officials have questioned the strategy and called it an obstacle to a successor to the 1991 START nuclear arms reduction pact, under negotiation for months. 


"While I think there are concerns that the Russians may raise going forward … we don't think this is a threat to the reset," Vershbow said. 
"There are a lot of good things going on in the bilateral relationship. So it's still a work in progress. But I think the reset worked and now we're trying to build a more cooperative, substantive relationship."