A war of words between a Republican senator from Missouri and the world’s biggest retailer erupted Wednesday, with President-elect Joe Biden’s inauguration less than a month away.

U.S. Sen. Josh Hawley said Wednesday he will raise objections next week when Congress meets to affirm Biden’s victory in the election, forcing House and Senate votes that could delay — but not alter — the final certification of Biden’s win.

Hawley said he would object because “some states, including notably Pennsylvania,” did not follow their own election laws. Lawsuits challenging Biden’s victory in Pennsylvania have been unsuccessful.

“At the very least, Congress should investigate allegations of voter fraud and adopt measures to secure the integrity of our elections,” Hawley said Wednesday.

Walmart then criticized Hawley in a now-deleted tweet, calling him a “sore loser.”

Hawley, who was elected in 2018, responded to Walmart’s comments, calling the global corporate giant to apologize for using “slave labor.”

Later Wednesday afternoon, Walmart issued an apology, saying the tweet had been “mistakenly” posted by a member of the company’s social media team.

President Donald Trump continues claiming there was widespread fraud in the election. He has pushed Republican senators to pursue his unfounded charges even though the Electoral College this month cemented Biden’s 306-232 victory and multiple legal efforts to challenge the results have failed.

A group of Republicans in the Democratic-majority House have already said they will object on Trump’s behalf during the Jan. 6 count of electoral votes, and they had needed just a single senator to go along with them to force votes in both chambers.

Asked about Hawley’s announcement, House Speaker Nancy Pelosi, D-California, said, “I have no doubt that on next Wednesday, a week from today, that Joe Biden will be confirmed by the acceptance of the vote of the Electoral College as the 46th president of the United States.”

When Congress convenes to certify the Electoral College results, any lawmaker can object to a state’s votes on any grounds. But the objection is not taken up unless it is in writing and signed by a member of the House and a member of the Senate.

When there is such a request, then the joint session suspends and the House and Senate go into separate sessions to consider it. For the objection to be sustained, both chambers must agree to it by a simple majority vote. If they disagree, the original electoral votes are counted.

The last time such an objection was considered was 2005, when Rep. Stephanie Tubbs Jones of Ohio and Sen. Barbara Boxer of California, both Democrats, objected to Ohio’s electoral votes by claiming there were voting irregularities. Both chambers debated the objection and rejected it. It was only the second time such a vote had occurred.

As president of the Senate, Vice President Mike Pence will preside over the Jan. 6 session and declare the winner.

The Associated Press contributed to this report.