Spain's competition watchdog on Thursday fined two natural gas traders a combined 4.8 million euros ($5.1 million) for not meeting deadlines to warn about changes in supplies to Spanish gas grid operator Enagas .

The regulator, known as CNMC, said it fined gas trading units of Germany's power utility RWE 3.6 million euros and French oil major TotalEnergies 1.2 million euros.

The two companies breached regulations on the unloading of liquefied natural gas from ships to regasification terminals in Spanish ports in 2021, CNMC said.

Companies are supposed to warn any change to Enagas at least five days in advance. The infringements were considered "grave", the CNMC said.

Spokespersons for Total and RWE did not immediately respond to requests for comment.

Following the Russian invasion of Ukraine and a diplomatic spat with Algeria, Spain is now getting most of its gas from seaborne LNG, whose price is much more volatile.

Earlier this year, dozens of ships loaded with LNG were circling off the Mediterranean coast, reportedly waiting for more favourable prices to unload.

($1 = 0.9389 euros)

(Reporting by Marta Serafinko, additional reporting from Tassilo Hummel; Editing by Inti Landauro, Mark Potter and Arun Koyyur)