A trade group representing Alphabet Inc., Facebook Inc. and other internet firms on Thursday backed a congressional reversal of the Trump administration’s December repeal of net neutrality rules.

U.S. Senate Democrats said last month they had the backing of 50 members of the 100-person chamber for repeal, leaving them just one vote short of a majority.

The Internet Association, which also represents Amazon.com Inc, Microsoft Corp and many others, said in a letter Thursday to Senate leaders it backed the Senate effort to reverse the vote, but also called for a legislative fix.

"The internet industry urges Congress to legislate a permanent solution,” the group said in the letter reviewed by Reuters.

A group of more than 20 U.S. state attorneys general are mounting a legal challenge to the Federal Communications Commission’s vote along party lines to reverse rules introduced in 2015 that barred internet service providers from blocking or throttling traffic or offering paid fast lanes, also known as paid prioritization. The new rules have not taken effect.