US senator Joe Lieberman was in Riyadh on Monday to meet with Saudi king Abdullah bin Abdul Aziz and other senior officials as part of a Middle East tour to discuss the Syria crisis, his office said. Lieberman also met with Saudi foreign minister Prince Saud al-Faisal, defence minister Prince Salman bin Abdul Aziz -- who recently held talks at the Pentagon with US defence secretary Leon Panetta to discuss the Syria crisis -- and General Intelligence chief Prince Muqrin bin Abdul Aziz. “The senator is traveling in the Middle East this week, focused on the continuing crisis in Syria and other issues related to US national security in the region,” Lieberman aide Whitney Phillips told AFP. It is the second trip to the region in three weeks for Lieberman, who chairs the Senate Homeland Security Committee and also sits on the Armed Services Committee. He visited a Syrian refugee camp in Turkey near the Syrian border earlier in April. Lieberman, along with Republican John McCain, have advocated further US intervention in Syria, including the arming of Syrian opposition groups against the regime of Syrian president Bashar al-Assad. And while he stressed he wants “no (US) boots on the ground” in Syria, he was adamant about the need to provide more substantive military aid. “At some point we simply have to say, ‘we’re going to help them, we\'re going to give them weapons to defend themselves,’ and that will make them strong and more organised,” Lieberman said last week at the Brookings Institution, a Washington think tank. On Sunday he was in Qatar, where he met with the minister of state for foreign affairs Khaled al-Attiyah, Phillips said.