U.S. Defense Secretary Robert Gates warned the United States' enemies on Saturday against trying to take advantage of the early months of the new Washington administration to test U.S. resolve.
Gates also said the United States would stay deeply involved in the Middle East and the Gulf under Barack Obama's administration.
"I can assure you that a change in administration does not alter our fundamental interests, especially in the Middle East," he told a regional security conference in Bahrain.
Many foreign policy experts, including vice-president elect Sen. Joe Biden, have suggested enemies of the United States will try to provoke a crisis early in Obama's term while the new administration is still finding its feet.
Gates, who will stay on under Obama, said extensive planning had gone into preparing for the transition.
"Anyone who thought that the upcoming months might present opportunities to test the new administration would be sorely mistaken," he told the Manama Dialogue conference, organized by the London-based International Institute for Strategic Studies.
"President Obama and his national security team, myself included, will be ready to defend the interests of the United States from the moment he takes office on January 20th," Gates said.
Gates, a former CIA director, said the security of the Gulf had long been a central concern for Washington and he brought a message of continuity and commitment from Obama to U.S. allies in the region.
He repeated longstanding appeals for Arab states to support Iraq's U.S.-backed government with full diplomatic relations and forgiveness of Saddam Hussein-era debts.
Gates said Arab states should welcome a chance to forge close relations with Iraq, partly to prevent Iran from doing so.
"There is no doubt that Iran has been heavily engaged in trying to influence the development and direction of the Iraqi government -- and not as a good neighbor," he said.
"Iraq wants to be your partner," he told his audience. "And, given the challenges in the Gulf, and the reality of Iran, you should wish to be theirs."
Gates restated U.S. complaints that Iran supports groups such as Hamas in the Palestinian territories and Hezbollah in Lebanon and said its nuclear program was "almost assuredly" meant to lead to atomic weapons -- a charge Tehran disputes.