WASHINGTON, July 16 (Xinhua) -- Softened from an earlier position, U.S. Secretary of Defense Robert Gates on Thursday raised the possibility to further increase U.S. troop levels beyond the enforcement plans announced by President Barack Obama.

    He made the comments during a visit to the Fort Drum military base in upstate New York.

    "I think there will not be a significant increase in troop levels in Afghanistan beyond the 68,000 (level) ... Maybe some increase, but not a lot," Gates was quoted as saying by the Washington Post on its website.

    According to Obama's plans announced earlier this year, U.S. troop levels in Afghanistan will grow to 68,000 by September.

    But Gates had been opposing further increases, citing worries that the United States might end up being trapped in Afghanistan by devoting too many troops and resources there.

    However, there has been a growing call from U.S. commanders in Afghanistan that under current plans, they may not have enough soldiers to pacify the volatile country.