Iran has seized two Greek tankers in helicopter-launched attacks in the Gulf amid a dramatic rise in tension and violent incidents in the region. Forces from the Islamic Revolutionary Guard Corps (IRGC) descended on the tankers – one of which was named as the Prudent Warrior – in helicopters in what appeared to be a reprisal for the Greek government’s role in assisting the US seizure of an Iranian oil tanker in the Mediterranean in a sanctions-enforcement action earlier in the week. With talks stalled among major powers and Iran on reviving a 2015 nuclear deal, there are increasing signs that Tehran and its enemies are prepared to resort to force to advance their interests. The Iranian defence ministry reported an “accident” at its high-security Parchin complex on Wednesday, which killed an engineer and injured another. The New York Times reported on Friday that it was an attack using quadcopter suicide drones, that fitted a pattern of Israeli operations against Iranian military and nuclear infrastructure. The report said the drone strike was aimed at a facility where Iran is developing its own drone technology. According to the Times, Israel has also informed the US that it was behind the assassination of an IRGC colonel, Sayyad Khodai, who was shot by gunmen on motorbikes as he was getting out of his car outside his home in Tehran on Sunday. An unnamed intelligence official was quoted as saying Israel intended the killing to serve as a warning to Tehran to stop targeting Israeli citizens abroad. On Thursday, the IRGC commander, Maj Gen Hossein Salami, said that there would be a response to the kill. “Our enemies should wait,” he said. “Our reactions will be harsh and we will definitely make the enemy regret its action,” Salami said, according to Press TV. If confirmed, the attack on Parchin would mark a sharp uptick in the covert drone war between Iran and Israel. In February, Israel is reported to have sent six quadcopter drones to hit an Iranian military drone manufacturing facility near the city of Kermanshah. In retaliation, Iran launched a missile strike on buildings inside Iraq which it believed were being used by Israeli intelligence to launch the attack on Kermanshah. The seizure of the Greek tankers in the Gulf was the first such action in several months in the Gulf. Greece’s foreign minister complained to the Iranian ambassador to Athens about the “violent taking over of two Greek-flagged ships” in the Persian Gulf. “These acts effectively amount to acts of piracy,” a ministry statement said, calling for the immediate return of the ships and their crews.