Updated at 10:58 a.m. ET

President Trump is threatening to veto a critical defense spending bill unless Congress agrees to repeal a liability shield for social media companies.

The president tweeted late Tuesday that Section 230 of the 1996 Communications Decency Act is "a serious threat to our National Security & Election Integrity."

Section 230 provides legal protection for technology companies over content from third parties and users. Trump referred to the provision as a "liability shielding gift" to "Big Tech."

If he doesn't get his way, Trump is threatening to nix this year's National Defense Authorization Act — a crucial piece of annual legislation that covers authorization for pay raises and other spending needs for the nation's military.

The veto threat is the latest move by the president in his war against social media giants such as Facebook and Twitter. He and other conservatives believe tech companies are biased against conservative political views — censoring posts they don't like. However, the social media platforms say they are only trying to stop the spread of false claims and disinformation.

Trump previously threatened a veto of the NDAA in July because it included language renaming U.S. military installations honoring Confederate generals.

Lawmakers from both sides of the aisle, who have largely rejected a wholesale repeal of Section 230, have nonetheless proposed revisions, in part to modernize the policy, but no concrete legislative steps have been taken.

Lawmakers on the NDAA conference committee are set to meet Wednesday over the legislation.

This is the 60th year Congress has crafted an annual defense policy bill and it usually passes with overwhelming bipartisan, veto-proof majorities.

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