WASHINGTON (Reuters) - U.S. Vice President Joe Biden and Ukrainian President Petro Poroshenko, who is visiting Washington to take part in a nuclear summit, will meet on Thursday, the White House said. Biden and Poroshenko will hold a working lunch, the White House said in a statement on Wednesday. President Barack Obama will convene leaders from more than 50 countries in Washington this week for his fourth and final Nuclear Security Summit. 
Biden, Ukraine's Poroshenko to meet Thursday: White House