title: Biden, Ukraine's Poroshenko to meet Thursday: White House
text: 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. 