San Francisco, Dec 28 (IANS): Tesla founder and CEO Elon Musk is seeking to dismiss a defamation lawsuit filed against him by a British cave rescuer who sued the billionaire for calling him a paedophile.

The motion was reportedly filed in the U.S. District Court in California on Wednesday.

"His attorneys have filed a motion to dismiss the case on the grounds that his insults weren't serious and thus were protected free speech in the US. This was just a 'schoolyard spat'," Musk's attorneys said.

They contended that Twitter is a place where you could "expect to read opinions, not facts," and thus "no one could realistically assume Musk was telling the truth", Engadget reported late on Thursday.

Whether these arguments will be enough to convince a judge to dismiss the lawsuit is unclear, the report added.

The cave diver, Vernon Unsworth, who aided the rescue of 12 boys from Thailand's Tham Luang caves, earlier said he would sue the Tesla boss for defamation in three countries -- Thailand, Britain and the US.

The two clashed over how to free the boys in an exchange that led to Tesla's chief calling Unsworth "paedo guy".

The "vituperative" exchange between Musk and Unsworth took place during frantic attempts to rescue the 12 boys and their coach from deep within the partially flooded caves in July 2018, according to the BBC.

Musk faced a widespread backlash after unsuccessfully attempting to assist the rescue mission and eventually apologised to Unsworth and deleted the offending tweet.

In an email to a journalist, Musk later launched a fresh tirade against Unsworth, without providing any document to support his allegations.

Musk called Unsworth a "single white guy from England who's been travelling to or living in Thailand for 30 to 40 years", alleging that he had moved to Chiang Rai "for a child bride who was about 12 years old at the time".