US Secretary of State John Kerry has repeatedly called leaders in Saudi Arabia and Iran to try to defuse their diplomatic row.
State department spokesman John Kirby said the phone conversations involved foreign ministers of both countries and the Saudi deputy crown prince.
Saudi Arabia cut diplomatic ties with Iran on Sunday after protesters ransacked the Saudi embassy in Tehran. The Protests erupted after Saudi Arabia executed a senior Shia Muslim cleric.
On Monday, the UN Security Council issued a strongly worded statement condemning the attack on the Saudi embassy – making no mention of the execution of Shia Muslim cleric Sheikh and 46 others on terrorism charges.
Turkey has also called for calm, warning that the feud could worsen regional tensions.
Iran has responded angrily to the diplomatic moves, insisting it had no hand in the violent protests that followed the execution.