By Roberta Rampton and David Shepardson

WASHINGTON (Reuters) - President Donald Trump welcomed prominent conservative social media provocateurs to the White House on Thursday and said that along with himself, they are being treated unfairly by big tech firms, which he says suppress conservative voices.

Trump said he has told his administration to look for regulations and legislation that could protect free speech - though he did not provide details on what measures were being discussed - and said he would summon major social firms to the White House for talks in coming weeks.

"We're not going to be silenced," Trump said, complaining about fluctuations in the number of his Twitter followers. "Big tech must not censor the voices."

Freedom of speech is enshrined in the First Amendment of the U.S. Constitution.

Trump, who regularly lashes out at the mainstream news media for their work which he brands as "fake news," made social media a key part of his 2016 run for office as well as his 2020 reelection campaign. But he and other Republicans have long claimed that online platforms employ tactics to silence their voices, allegations that major social media companies have denied.

Dozens of pro-Trump online personalities convened in the stately East Room to discuss what they say is censorship on social media platforms, rubbing elbows with several members of Trump's cabinet and his White House team, and his son Donald Trump, Jr.

Amid the sea of suits, several red Trump campaign hats and rubber bracelets popped out. Singer Joy Villa, who describes herself as a conservative activist, wore a flamboyant stars-and-stripes formal gown.

Trump called to the stage Lila Rose, an anti-abortion activist who has been blocked from Pinterest; California lawyer Harmeet Dhillon, who has represented conservatives in free-speech lawsuits; and Lynnette Hardaway and Rochelle Richardson, sisters and video bloggers who are better known as Diamond and Silk.

Carpe Donktum, a pro-Trump online persona who was recently suspended by Twitter for eight days over a video depicting Trump as a cowboy attacking CNN journalist Jim Acosta, said the face-to-face event could unite online conservatives.

In freewheeling remarks that bounced from one topic to another - not unlike his Twitter feed followed by more than 61 million people - Trump talked about the power of social media, and railed against the traditional media standing at the back of the room.

"We hardly do press releases anymore," Trump said. "If I put it out on social media, it's like an explosion."