In his Oval Office speech next Tuesday night, President Barack Obama will signal a shift in U.S. focus from the Iraq war to the conflict in Afghanistan, the White House said Thursday. Obama administration officials portrayed next week's speech as an important pivot from Iraq, a war that candidate Obama said should never have been fought, to Afghanistan, a conflict that President Obama sees as vital to the country's security. Previewing the speech as Obama vacationed on Martha's Vineyard, Massachusetts, deputy spokesman Bill Burton said Obama also will thank U.S. soldiers who have acted bravely in Iraq. With the formal U.S. combat mission at its end, troop strength in Iraq this week fell below 50,000 for the first time since the 2003 U.S.-led invasion. Many of those soldiers will remain in training and advising roles. Burton said the speech “commemorates an important milepost in American history.” He said the president will use the occasion to speak “directly with the American people about what our mission is in Afghanistan [and] the fact that more of our efforts and focus are now on fighting al Qaida in Afghanistan.