Updated

Tweaking one word in the name of a landmark normally wouldn't cause a diplomatic fracas. Except when that word is "Persian," and it's changed to "Arabian."

The U.S. Navy has invited outrage from Iranian advocacy groups, the Iranian government and Facebook protesters for making it official policy to call the Persian Gulf the Arabian Gulf. Though the Navy claims it's been using the term for two decades, the Pentagon was bombarded with complaints over the past week after the language showed up in the Navy's official style guide online.

Now what began as a cyberprotest on Facebook may be escalating into a new rift between Washington and Tehran at an already tense time.

"This only fuels those tensions," said Jamal Abdi, policy director with the National Iranian American Council, an advocacy group for Iranian Americans based in Washington, D.C. "This is an ethnically divisive term. ... It's very troubling."

Abdi said Washington is playing "name games" which could have "dangerous" consequences.

The nomenclature regarding the body of water that separates Iran from Saudi Arabia and other Arab states is a bigger sticking point than one might expect. The name has become a point of cultural pride, after some Arab nations began calling it the Arabian Gulf in the 1960s -- though it was known for centuries as the Persian Gulf and continues to be labeled as such on modern maps.

Iran's government, representing the land formerly known as Persia, has scolded any country that even hints at using the new term, and this time was no different.

In the wake of the Navy's decision, Tehran reportedly has summoned the Swiss ambassador to lodge a protest against the United States -- the Swiss represent U.S. interests in Iran, in the absence of U.S.-Iran diplomatic relations.

A State Department official told FoxNews.com the department could not go into the details of "diplomatic exchanges." According to the Tehran Times, a deputy foreign minister for Iran told the Swiss envoy that historical records establish Persian Gulf as the correct name -- a Foreign Ministry spokesman said the U.S. decision to use a different term puts its credibility in question.

This was after the U.S. Navy Style Guide online specified that Arabian Gulf should be used "instead of Persian Gulf."

Lt. Myers Vasquez, a Navy spokesman, told FoxNews.com on Friday he's not sure when the style guide entry was published or how it first started to attract attention. But he said the Navy, which operates a major base in Bahrain, has used the term Arabian Gulf unofficially for more than 20 years.

He suggested the term was employed out of deference to U.S. allies in the region.

"It's not something we just changed," he said. "Our partners in the region use it, and so do we."

But the use of the term does not appear to be military-wide. The Defense Department's 2009 style guide calls it the Persian Gulf, explicitly stating, "Do not use 'Arabian Gulf'" as there's already an Arabian Sea. The terms "Persian Gulf War" and "Gulf War" have traditionally been used interchangeably to describe the 1990-1991 war in Iraq.

The terminology has become such a contentious issue that the United Nations has repeatedly weighed in.

U.N. directives in 1994 and 1999 said Persian Gulf should always be used. A U.N. working group produced a document in 2006 establishing the history behind the name, including in contracts signed between countries dating back centuries.

So after the U.S. Navy called it the Arabian Gulf, "cause" groups started to pop up on Facebook and users began assailing the Navy's page with thousands of complaints.

At first, the Navy posted a message on its wall welcoming the discussion. The Navy posted a subsequent message last Friday explaining "'Arabian Gulf' is the naming convention recognized by our regional Arab partner nations and used by the U.S. Navy in the 5th Fleet area of operations."

Then it posted again to state "the continuous disruptive posts" were not benefiting most fans of the site and would be deleted.

But the comments still show up all over the page.

"Persian Gulf is the official name. ... . Iranians are not supporting Ahmadinejad. But many arabs do," one said.

"History can not be changed by US nor any of its partners," said another.

"PERSIAN GULF FOREVER!!!!" said another.

Vasquez said the Facebook complaints have started to die down. But other groups have launched petitions or letters to register their complaints with the military.

The National Iranian American Council claims to have attracted 4,000 signatures for an online letter to Defense Secretary Robert Gates protesting the Navy's policy.

"The Navy's official use of this term will only exacerbate tensions in the Middle East," it says, noting the contents of State Department cables recently leaked by WikiLeaks. Those cables showed Arab leaders urging the United States to attack Iran's nuclear facilities.

Abdi said the term only fuels "enmity" and is a shot at Iranians. "It's also insulting to people of history and people who read maps," he said. He noted that his organization also protested after a State Department official used the term in October.

He was referring to Andrew Shapiro, an assistant secretary for political-military affairs, who referred to the "Arabian Gulf" during a briefing on a multibillion-dollar arms sale with Saudi Arabia.

A State Department official cautioned against reading too much into the incident, saying there was no "set policy" on which term to use.