Rupert Murdoch. REUTERS/Mike Blake Rupert Murdoch urged Republican presidential candidate Donald Trump to relax a little bit on Thursday.

"Trump blames me for WSJ poll, fights Fox News. Time to calm down. If I [am] running anti-Trump conspiracy then [I'm] doing lousy job!" Murdoch exclaimed on Twitter.

Murdoch, CEO of News Corp., was responding to Trump's furious attacks against Fox News and The Wall Street Journal, two of his media properties.

The Journal and NBC News published a joint national poll on Wednesday that showed Trump narrowly behind Ted Cruz, a top GOP primary rival, for the first time. The poll differed significantly from several other national surveys that gave Trump a wide lead.

At a Thursday campaign rally in Kiawah Island, South Carolina, Trump lit into The Journal.

"They have like an outlier poll ... and today it's on the front page of The Wall Street Journal. What a lot of crap! OK? Isn't it? It's disgusting," Trump said.

"In my opinion, it's a phony poll," he added.

One of Trump's top campaign advisers strongly suggested on Thursday that Murdoch had something to do with The Journal's poll:

Additionally, Trump has raged for months at Fox News, another News Corp. property, over its allegedly unfair coverage of his campaign. Trump even famously boycotted the network's presidential debate last month.

Trump's complaints about Fox News again exploded out into the open this week after Fox interviewed Lindsey Graham, a Republican senator and frequent Trump critic:

Trump later criticized The Journal and Fox News in the same tweet: