President Barack Obama has called King Abdullah of Saudi Arabia and King Hamad bin Isa Al Khalifa of Bahrain to express deep concern over the violence in Bahrain.
White House spokesman Jay Carney said Obama stressed the need for "maximum restraint" while speaking to both of the leaders on Wednesday.
Saudi Arabia and other Gulf countries have sent hundreds of troops to assist security forces in Bahrain.
Obama's intervention comes as the unrest in Bahrain has grown increasingly violent.
Soldiers and riot police expelled hundreds of protesters from a landmark square in Bahrain's capital on Wednesday, using tear gas and armored vehicles to try to subdue the challenge to the 200-year-old monarchy.
Carney said Obama emphasized the political process is the only way to lead to a stable Bahrain.