Nearly a dozen small craft operated by the naval wing of Iran's Revolutionary Guard carried out harassing maneuvers dangerously close to U.S. warships conducting exercises in the Persian Gulf, Navy officials said Wednesday.

"The [Islamic Revolutionary Guard Corps navy] vessels repeatedly crossed the bows and sterns of the U.S. vessels at extremely close range and high speeds, including multiple crossings of the [USS Lewis B.] Puller with a 50 yard closest point of approach (CPA) and within 10 yards of [the U.S. Coast Guard Cutter] Maui's bow," the U.S. Navy's Bahrain-based 5th Fleet said in a statement.

The Puller, an expeditionary mobile base vessel, and the Maui are part of a larger U.S. flotilla conducting joint integration operations with U.S. Army AH-64E Apache attack helicopters in the international waters of the North Arabian Gulf — also known as the Persian Gulf — according to the Navy.

"The U.S. crews issued multiple warnings via bridge-to-bridge radio, five short blasts from the ships' horns and long range acoustic noisemaker devices, but received no response from the IRGCN," the Navy said. "After approximately one hour, the IRGCN vessels responded to the bridge-to-bridge radio queries, then maneuvered away from the U.S. ships and opened distance between them."

The Navy said the actions of the Iranian vessels were "dangerous and provocative" and "increased the risk of miscalculation and collision."

Iranian officials did not immediately comment, but the country's semiofficial Fars news agency acknowledged the incident, according to The Associated Press.

The close approach at sea came as armed Iranian speedboats boarded and then briefly detained the Hong Kong-flagged chemical tanker SC Taipei in the Gulf of Oman, directing it to Iranian waters before allowing it to proceed.

"The vessel was approached 48nm (nautical miles) offshore Fujairah and hailed by four skiffs carrying armed Iranian coastguard personnel," British maritime security company said. "The vessel's crew were ordered to lower the ladder and were then boarded. The vessel was later directed to Kooh Mobarak, Iran, but quickly released with crew and vessel now confirmed safe."

In a series of incidents last year, the U.S. accused Iran of attacking tankers in the Persian Gulf and Iran seized the British-flagged tanker Stena Bulk and held it for several weeks. The British Royal Marines later seized an Iranian tanker, the Grace 1, in waters near Gibraltar.

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