Sen. Joe Manchin (D., W.Va.) on Wednesday said presidential candidate Beto O'Rourke "is not taking my guns away from me."

O'Rourke, a former congressman from El Paso, Texas, has made gun confiscation part of his presidential platform in a bid to capture voters on the left. His poll numbers have been flagging, but he gained a great deal of media attention at last week's debate by saying "hell yes" he would confiscate AR-15s.

Manchin was not impressed.

"I can tell you one thing: Beto O'Rourke's not taking my guns away from me. You tell Beto that OK?" Manchin told Wall Street Journal reporter Lindsay Wise.

Manchin also said it was "very harmful" to the Democratic Party for O'Rourke to make it look like Democrats want to seize lawfully owned firearms.

"Beto's one human being. He gave his own opinion, OK? I think it was very harmful to make it look like all the Democrats," Manchin said.

Dem Sen. @JoeManchinWV on Beto pledge to confiscate AR15s: "Beto's one human being. He gave his own opinion, OK? I think it was very harmful to make it look like all the Democrats. I can tell you one thing: @BetoORourke's not taking my guns away from me. You tell Beto that OK?" — Lindsay Wise (@lindsaywise) September 18, 2019

In the United States, there are an estimated 16 million AR-15s and AK-47s—the two types of rifles O'Rourke said he would confiscate as president. The FBI found rifles of any kind were used in only 403 murders in 2017, far fewer than handguns. But many gun control advocates in the media and the Democratic Party have targeted the AR-15.

O'Rourke's campaign immediately went after Manchin on Twitter. His national director of rapid response, Lauren Hitt, dismissed Manchin's opinion because he voted to confirm Supreme Court Justice Brett Kavanaugh, who has faced an onslaught of sexual assault accusations from the left.

Let me tell you how much I care about the opinion of the Democrat who voted to confirm Kavanaugh https://t.co/LYDUdSY903 — Lauren Hitt (@LaurenHitt) September 18, 2019

During the Democratic presidential debate in Houston Thursday, O'Rourke made his position on so-called assault weapons clear.

"Hell yes, we're going to take your AR-15, your AK-47," he said. "We're not going to allow it to be used against our fellow Americans anymore."

O'Rourke's debate performance did not stop his slide in the polls. In the latest NBC News/Wall Street Journal poll, O'Rourke is at 1 percent, down from 2 percent in July.

Some in the media have questioned whether O'Rourke has helped gun control efforts. MSNBC host Andrea Mitchell said it would be harder to pass gun legislation after O'Rourke called to confiscate guns from lawful owners. For Democrats and the media, it has long been a talking point that "no one" wants to take guns away from civilians.