WASHINGTON, Jan. 11 (Xinhua) -- U.S. Secretary of State Condoleezza Rice said on Thursday that the United States will not "stand idly by" if Iran tries to disrupt Washington's renewed effort to stabilize Iraq.

    Defending Bush's new Iraq strategy in television interviews and testimony in Congress, Rice said that the United States is determined to crack down on Iran's "regional aggression."

    "I don't want to speculate on what operations the United States may be engaged in, but you will see that the United States is not going to simply stand idly by and let these activities continue," Rice said in one interview.

    The U.S.-Iran ties have been in tension for decades. Washington accuses Iran and Syria of supporting insurgents and terrorists in Iraq, and has vowed to stop alleged Iran's support for attacks on American troops in Iraq. ¡¡