Iran has launched a naval exercise in the Indian Ocean, to test out two of its newest domestically-built warships. The drill takes place amid tensions with the US, and days after Iran seized a South Korean tanker.

The Iranian Navy’s Deputy Commander for Coordination, Rear Admiral Hamzeh Ali Kaviani, said the purpose of the two-day ‘Eghtedar 99’ drill is to test the ability to “react in a timely and effective manner” against enemy threats.

The domestically-built ‘Makran’ helicopter carrier officially joined the Navy on Wednesday. A Press TV reporter described the new vessel as one of the “biggest and largest” warships ever developed by Tehran. Local media reported that it can travel for 1,000 days without docking.

Navy Commander Rear Admiral Hossein Khanzadi was quoted as saying that the ship can carry seven helicopters. According to reports, the ‘Makran’ will support other warships during operations in the Indian Ocean, the Red Sea, and the strategic Bab-el-Mandeb Strait, which connects the Red Sea with the Gulf of Oman.

Another ship that has joined the Islamic republic’s Navy is the missile frigate ‘Zereh,’ tasked with defending the country’s southern waters.

The drill takes place amid heightened tensions between Iran and the US, whose “maximum pressure” sanctions campaign has targeted Iran’s energy and financial sectors. The countries were seemingly on the brink of war at the beginning of last year, when an American airstrike in Iraq killed a top Iranian military commander.

Last week, the Pentagon reversed its decision to pull the aircraft carrier USS Nimitz from the Middle East. The ship will stay in the region “due to the recent threat issued by Iranian leaders against President Trump,” acting Defense Secretary Christopher Miller said.

The situation has also remained tense due to Iran’s occasional seizure of tankers in the Persian Gulf, and the allegations that Tehran had ordered the bombing of tankers in the Gulf of Oman in 2019. Officials in Iran have denied any involvement in these attacks.

On January 4, Iran seized a South Korean tanker, citing environmental violations. The incident occurred as Tehran was demanding that Seoul unblock the country’s assets held in South Korean banks.