Bahrain's king says his country will stand against foreign interference — a clear reference to Iran — in clashes between the Sunni-led ruling system and majority Shiites seeking a greater political voice.

The comments Sunday to parliament by King Hamad bin Isa Al Khalifa are part of efforts to link Iran to the 20-month Shiite uprising in the strategic Gulf nation, home to the U.S. Navy's 5th Fleet. Iran has denounced the violence, and there is no firm evidence of Tehran aiding the protesters.

Bahrain presents a difficult challenge for Washington, which seeks to keep its military ties but also has expressed concern about the unrest that has claimed more than 50 lives.

Shiite opposition groups claim the government is not willing to hold full-scale dialogue on political reforms.