On January 12, 2016, two United States Navyriverine command boats were seized by Iran's Islamic Revolutionary Guard Corps (IRGC) Navy after they entered Iranian territorial waters near Iran's Farsi Island in the Persian Gulf. Initially, the U.S. military claimed the sailors inadvertently entered Iranian waters owing to mechanical failure, but it was later reported that they entered Iranian waters because of navigational errors. The U.S. secretary of state, John Kerry, called the Iranian foreign minister Mohammad Javad Zarif within five minutes. His call was followed by multiple other phone calls between the two ministers. The sailors had a brief verbal exchange with the Iranian military and were released, unharmed, 15 hours later.