RIYADH — Gulf Cooperation Council (GCC) countries and the United States have agreed to carry out joint patrols to stop any Iranian arms shipments reaching Yemen, GCC Secretary General Abdullatif Al-Zayani said on Wednesday. Zayani was speaking at a news conference with US Defense Secretary Ash Carter after a meeting between Carter and his counterparts from the GCC. The GCC-US also agreed to cooperate in building the GCC states' joint missile defense systems and in developing special forces. At the outset of the GCC-US defense ministers' meeting at Al-Diriyah palace, Deputy Crown Prince Muhammad Bin Salman, second deputy premier and minister of defense, called for united efforts to defeat the challenges facing the region, the most important of which are terrorism, instability and Iranian interference in the affairs of the region's countries. He said the meeting focussed on the work to meet these challenges together through the long and deep-rooted partnership between the GCC and the United States. "Today we must work seriously to confront these challenges by working together," said Deputy Crown Prince Muhammad. US Secretary of Defense Ash Carter said the United States and GCC nations were "building on that strong partnership" that has lasted for decades. A senior defense official said the two major focuses of Carter's visit are countering Iran's destabilizing activities and defeating Daesh (the so-called IS). Earlier in a separate meeting, Carter told Deputy Crown Prince Muhammad that the Kingdom and the US should deepen bilateral cooperation on training for special operations and integrate missile defense systems, Pentagon press secretary Peter Cook said in a statement on Monday. "Carter identified several areas where the United States and Saudi Arabia can deepen their security cooperation for the benefit of both countries, such as enhancing training for special operations and counterterrorism forces, integrating air and missile defense systems, bolstering cyber defenses, and strengthening maritime security," Cook said. The Pentagon statement noted that the two leaders also discussed mutual security issues, "including checking Iranian destabilizing activities in the region and countering violent extremism" from groups like Daesh.