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DUBAI, July 7 (Reuters) - The United States conveyed a message to Iran warning of a limited strike against the country after its unmanned drone was shot down in the Gulf, Iran's civil defence agency chief was quoted as saying by the Fars news agency on Sunday.

"After the downing of its intruding drone, the United States told us through diplomatic intermediaries that it wanted to carry out a limited operation," said Gholamreza Jalali, who is also a senior commander of Iran's elite Revolutionary Guards.

"But Iran's response was that we regard every operation as the beginning of a war."

A day after the drone was downed in the Gulf, Iranian officials told Reuters on June 21 that Tehran had received a message from U.S. President Donald Trump through Oman after the drone was downed, warning that a U.S. attack on Iran was imminent. Iranian and U.S. officials denied the report.

Trump later said he had approved retaliatory military strikes against Iran, but called them off at the last minute.

The shooting of the drone came after weeks of rising tension following a spate of attacks on oil tankers in the Gulf region. Tehran said the drone had violated its airspace. Washington denied this. (Writing by Parisa Hafezi;Editing by Elaine Hardcastle)