(Adds details, quotes throughout) By Kristin Roberts WASHINGTON, July 26 (Reuters) - The Pentagon is making contingency plans for a gradual U.S. withdrawal of troops from Iraq, according to U.S. Defense Secretary Robert Gates, who called the planning a "priority." In a letter delivered on Tuesday to Sen. Hillary Clinton, a New York Democrat and presidential candidate who tangled with the Pentagon to learn whether such plans exist, Gates said he was actively involved in drafting them. He said he would work with the Senate Armed Services Committee to find a way to keep senators informed about the "conceptual thinking, factors, considerations, questions and objectives associated with drawdown planning." "You may rest assured that such planning is indeed taking place with my active involvement as well as that of senior military and civilian officials and our commanders in the field," Gates said. "I consider this contingency planning to be a priority for this department." Pentagon spokesman Bryan Whitman stressed the Pentagon was not planning for a quick or wholesale withdrawal of forces. A phased reduction would be in line with a Bush administration view that some long-term U.S. presence in Iraq may be needed. "Planning for reducing our forces, drawing down our forces, is certainly something that is an appropriate thing to do," Whitman said. "We are doing that kind of planning, planning for the eventual drawdown, eventual reduction, the beginning of withdrawing of forces from Iraq." The Defense Department develops contingency plans for a range of scenarios worldwide. This spring some 30,000 more U.S. troops were sent to Iraq, bringing the total force to about 157,000, under the current plan aimed at establishing enough security to allow Iraqi politicians to make progress toward reconciliation. All of the so-called "surge" forces have been in place since June 15. Democrats in Congress, however, are calling for a strategy change leading to withdrawal. Clinton had asked the Pentagon in May for information about contingency planning for a possible troop withdrawal from Iraq. Defense Under Secretary Eric Edelman, in the Pentagon's written response, did not address whether the Defense Department was making such plans. Instead, he said public discussion of withdrawal "reinforces enemy propaganda that the United States will abandon its allies." Clinton called the response unacceptable and outrageous. Gates, in a follow-up letter, backed Edelman, noting the official was given his first senior presidential appointment as an ambassador in 1998, during the administration of the senator's husband, former President Bill Clinton.
