(CNN) -- The back-and-forth between Iran and the United States over an encounter between their naval forces intensified this week when Tehran rejected a message from Washington because it did not use the term "Persian Gulf," Iran's news agency said.
A suspected Iranian boat maneuvers near U.S. Navy ships on January 6.
The Iranian Foreign Ministry wouldn't acknowledge the message because it twice used the word Gulf instead of Persian Gulf when referring to the January 6 incident between U.S. warships and Iranian patrol boats in the Strait of Hormuz, a ministry official told the state-run news agency, IRNA, on Wednesday.
Iran, a country known to the West as Persia until the 1930s, insists the body of water between its southern coast and the Arabian Peninsula be referred to by its historic name Persian Gulf. Some Arab countries have called it the Arabian Gulf.
A working paper submitted to the U.N. Group of Experts on Geographical Names in 2006 said: "If we were to presume that the sea did not have a name during history, and ... geographers and specialists were to select a name for this gulf, doubtlessly, they would find no better name than Persian Gulf because Iran [Persia] is the largest country adjacent to this water body which possesses the longest coast."
The United States sent the message to Iran via the Swiss Embassy four days after the encounter in the Strait of Hormuz -- at the entrance to the Persian Gulf -- where much of the region's oil shipping originates.
The United States contends its warships received a threatening radio transmission telling the U.S. fleet they would "explode." The Pentagon released a four-minute, 20-second videotape that showed five boats racing back and forth near the convoy.
Iran, which also released video footage of the incident, maintains it was a routine communication. The Islamic republic accuses the United States of faking the video and exaggerating the matter for political purposes.
Ali-Akbar Rezaie, the head of the ministry's American Affairs Department, told the Iranian news agency his government will consider the content of any U.S. message once a "revised version is received." E-mail to a friend