Increased US military activity in the Persian Gulf is meant to counter "very negative" behavior by Iran and undercut its belief that American forces are overcommitted in Iraq, US Defense Secretary Robert Gates said Monday. Gates said the time is not right for diplomatic talks with Iran, but left open that possibility for the future. After meeting with senior officials at NATO headquarters, Gates was asked at a news conference what was behind the Bush administration's decision to deploy a Patriot missile battalion and a second aircraft carrier to the Gulf region - moves announced in connection with a further buildup of ground troops in Iraq. He noted that the United States has taken a leading role in Gulf security for many decades. "We are simply reaffirming that statement of the importance of the Gulf region to the United States and our determination to be an ongoing strong presence in that area for a long time into the future," he said.