WASHINGTON (Reuters) - U.S. President Barack Obama will host the leaders of Denmark, Finland, Iceland, Norway and Sweden in May for a U.S.-Nordic Leaders Summit, the White House said on Friday. The leaders will discuss terrorism, violent extremism, environmental and nuclear security issues among other topics at the summit on May 13, the White House said in a statement. Obama last met with Nordic leaders during his trip to Sweden in September 2013, the statement said. 