Qatar's state-run energy firm said on Monday it had halted liquefied natural gas production following Iranian attacks on facilities at two of its main gas processing bases.
"Due to military attacks on QatarEnergy's operating facilities in Ras Laffan Industrial City and Mesaieed Industrial City in the State of Qatar, QatarEnergy has ceased production of liquefied natural gas (LNG) and associated products," the company said in a statement.
Earlier, Qatar's defense ministry said one Iranian drone "targeted an energy facility in Ras Laffan Industrial City, belonging to QatarEnergy", referring to the firm's onshore gas processing base 80 kilometres (50 miles) north of Doha.
Another "targeted a water tank belonging to a power plant in Mesaieed", the statement said, referring to an area 40 kilometres (25 miles) south of the Qatari capital, which is also a key site for Qatar's natural gas production.
There were no reports of casualties, the defense ministry added.
The Dutch TTF natural gas contract, considered the European benchmark for LNG prices, jumped almost 45 percent to more than 46 euros ($54).
Jamie Ingram, managing editor of Middle East Economic Survey (MEES), said the halt was "an unprecedented development, with Ras Laffan the largest single LNG facility on the planet," warning there was "scope for prices to rise significantly".
He said the move was "made from an abundance of caution rather than one forced by the scale of the drone attack earlier today".
"It's possibly also intended to drum up international support," Ingram added.
Justin Alexander, an economic expert on Gulf issues and director of Khalij Economics, said it was "clearly a precautionary move" given strikes on Ras Laffan and risks to "extremely flammable gas facilities", adding the main market impact was "the closure of Hormuz", blocking nearly a quarter of global supply.
He added that the QatarEnergy suspension "could increase the delay to the resumption of normal supplies once Hormuz reopens".
While Iran has not officially closed the Strait of Hormuz, through which around 20 percent of global seaborne oil passes, its Revolutionary Guards have warned against transiting the waterway, leaving it effectively shut.