"The biggest challenge facing any state ... is preserving its national unity against foreign and domestic threats"
Gulf Arab states pledged to fight "terrorism" and "foreign interference" across the region.
In a joint statement following a summit in Riyadh, interior ministers of the six-nation Gulf Cooperation Council said they were determined to prevent "harm to their national unity, the provoking of sectarian tensions and support for terrorist groups".
The GCC states regularly accuse Iran of interfering in their internal affairs, particularly of stirring unrest in Bahrain and supporting Shiite rebels in Yemen -- charges Iran denies.
They said GCC states had shown determination to build bridges of cooperation with other states in the region.
"The biggest challenge facing any state in the modern world is preserving its national unity against foreign and domestic threats," said Saudi Interior Minister Prince Mohammad bin Naif, who chaired the summit.
The GCC states "continue to face dangerous challenges emanating from Iranian and Iraqi soil," he said.
Sunni-ruled Bahrain has been the scene of frequent protests and clashes with police since security forces quelled Shiite-led nationwide protests in 2011 that called for political reforms.
Saudi Arabia is leading an Arab coalition that in March 2015 launched a military campaign against Iran-backed Shiite Huthi rebels in support of President Abedrabbo Mansour Hadi.