LONDON (Reuters) - Britain will not block attempts by the European Union to forge a closer common defense policy as it negotiates its exit from the bloc, British Foreign Secretary Boris Johnson said on Friday.

Defense minister Michael Fallon had previously said he would stop the creation of an EU army for as long as Britain remained inside the European Union as the new force would undermine the NATO military alliance.

"There is a conversation going on now about the EU's desire to build a common security and defense policy, new architecture for that," Johnson told a London audience on Friday.

"If they want to do that fine ... We are not there to block or to impede further steps towards EU integration if that is what they so desire," he said.

(Reporting by Kylie MacLellan, writing by Costas Pitas)