WASHINGTON, Feb 22 (Reuters) - The annual summit of the United States and the European Union, to be held in Washington on April 30, will focus on Iraq, terrorism and nuclear proliferation, the White House said on Thursday. The gathering of U.S. and European leaders will come after the United States announced its decision to send 21,500 more troops to Iraq and Britain decided to reduce its forces. It also will follow the U.N. nuclear watchdog's report that Iran had failed to meet a deadline to suspend uranium enrichment, which exposes Tehran to possible new sanctions. "This meeting will underscore the importance of our relationship in addressing global challenges," White House spokeswoman Dana Perino said in a statement. "The president and the EU leaders will discuss a wide range of issues, including preventing nuclear proliferation; combating the global threat of terrorism; assisting reconstruction in Iraq and Afghanistan; and promoting peace and democracy in Europe, the Middle East, and Africa," she said. Trade, energy and climate change will also be on the agenda, she said.