WASHINGTON (Reuters) - A drop in U.S. troop levels in Iraq is ""inevitable over time"" but U.S. forces face many more years of combat against ""violent jihadist networks"" around the world, Defense Secretary Robert Gates said on Monday.

The Pentagon chief made the remarks in a speech to cadets at the U.S. Military Academy at West Point, New York, according to a text released by the Pentagon ahead of the evening event.
While stressing the United States must remain engaged in Iraq ""to avoid an even uglier fight or even greater danger to our country in the future,"" Gates said troop levels would decline further.
""A drawdown of U.S. force levels in Iraq is inevitable over time -- the debate you hear in Washington is largely about pacing,"" Gates said.
""But the kind of enemy we face today will not allow us to remain at peace,"" he said.
""What has been called the 'Long War' is likely to be many years of persistent, engaged combat all around the world in differing degrees of size and intensity,"" Gates said.
""This generational challenge cannot be wished away or put on a timetable. There are no exit strategies.""
The United States has 161,000 troops in Iraq and commanders plan to take stock of force levels in the summer, after completing a round of withdrawals that should leave around 140,000 U.S. military personnel in the country.
""Another war in the Middle East is the last thing we need and, in fact, I believe it would be disastrous on a number of levels,"" Gates said, according to the prepared text of his speech released by the Pentagon.