MUSCAT (AFP) - US Secretary of State Hillary Clinton paid a brief visit to Oman Wednesday for talks with Sultan Qaboos on rising tensions with Iran over its alleged plot to kill a Saudi envoy, officials said. A key Gulf ally, Oman helped secure since September 2010 the release of three US hikers jailed in Iran, two of them last month, earning gratitude from the United States. Now Washington is hoping to tap into Omans influence with the Islamic republic of Iran and share US concerns about Irans behaviour, particularly an alleged Iranian plot to murder the Saudi ambassador to Washington.