A top Iranian security official on Tuesday accused Saudi Arabia of using "cold war era" scare tactics in Yemen, after an air drop of leaflets that criticise "Persian expansion".
The reference, to Iran's language and ancient name, was contained on white paper fliers released from Saudi aircraft in recent weeks.
As the Middle East's foremost Sunni and Shiite powers, Saudi Arabia and Iran are increasingly seen as vying for supremacy in the region, which remains beset by conflict and political turmoil.
The conflict in Yemen, where a Saudi-led coalition of Sunni Arab states launched air strikes on March 26 against Huthi Shiite rebels whom Riyadh accuses Tehran of arming, has exposed their deteriorating relations.
"Dropping these leaflets, as untrue as they are, has the goal of frightening the Yemeni people," Ali Shamkhani, secretary of Iran's Supreme National Security Council, was quoted as saying.
The joint command of the Saudi-led Operation Decisive Storm has ordered that leaflets be dropped over Yemen. (Al Arabiya)
An AFP correspondent in Sanaa said the leaflets were dropped for two weeks during Operation Decisive Storm, the name given to the air campaign which officially ended last week. Air strikes, however, have continued.
The leaflet, in Arabic, said: "My brother of Yemen. The real goal of the coalition is to support the people of Yemen against the Persian expansion."
However, Shamkhani, a close adviser of Iran's supreme leader Ayatollah Ali Khamenei, countered by saying Iran was helping in Yemen by opposing the air strikes and providing aid.
"They say the Iranian brothers were the only ones who came to our help and received our wounded," Shamkhani cited Yemenis as saying, describing the leaflets as "simplistic" and accusing Saudi officials of backward thinking.
"This is a technique that western governments used to frighten people in the cold war era," he said.
"This action by Saudi Arabia is repeating that failed western method, and shows how old the minds of Saudi politicians are."
Iran summoned the Saudi charge d'affaires in Tehran on Friday to protest after the kingdom's fighter aircraft allegedly turned back humanitarian aid flights headed for Yemen from Tehran.
Relations have been steadily worsening between Iran and Saudi because of the fighting in Yemen, leading to heavy criticism by Khamenei and other top officials.
"What the Saudi government is doing in Yemen resembles exactly what the Zionist regime did in Gaza. This is a massacre, a genocide," Khamenei said on April 9.
And on Monday, Iran's Revolutionary Guards chief said the kingdom was verging on collapse as Tehran's regional position strengthens, accusing Saudi of "stepping in the footsteps of Israel and the Zionists" by bombing Yemen, the Arab world's poorest state.