President Donald Trump continued his call for a "Great Wall" at the border with Mexico on Tuesday morning, claiming Democrats want open borders rather than security and threatening to have the U.S. military build the wall if Democrats block funding.

Trump pressed his case in a five-part message on Twitter, posted ahead of his meeting with Senate Minority Leader Chuck Schumer, D-N.Y., and House Minority Leader Nancy Pelosi, D-Calif.

A combination of newly built walls, the Border Patrol, ICE, and the military have done a "fantastic" job, Trump said, but more is needed.

"Despite the large Caravans that WERE forming and heading to our Country, people have not been able to get through our newly built Walls, makeshift Walls & Fences, or Border Patrol Officers & Military," Trump said. "They are now staying in Mexico or going back to their original countries."

"Ice, Border Patrol and our Military have done a FANTASTIC job of securing our Southern Border," he continued. "A Great Wall would be, however, a far easier & less expensive solution. We have already built large new sections & fully renovated others, making them like new."

Democrats, however, "for strictly political reasons and because they have been pulled so far left, do NOT want Border Security. They want Open Borders for anyone to come in," Trump tweeted. "This brings large scale crime and disease. Our Southern Border is now Secure and will remain that way."

He added he was looking forward to meeting with Schumer and Pelosi, but "in 2006, Democrats voted for a Wall, and they were right to do so," he said. "Today, they no longer want Border Security. They will fight it at all cost, and Nancy must get votes for Speaker. But the Wall will get built."

The wall restorations have also been effective, he tweeted.

"People do not yet realize how much of the Wall, including really effective renovation, has already been built," Trump said. "If the Democrats do not give us the votes to secure our Country, the Military will build the remaining sections of the Wall. They know how important it is!"

He followed up with another tweet praising Michael Anton, a former senior national security official from the Trump administration, for a "great job" after he had appeared on Fox News' "Fox and Friends" around the time Trump was tweeting his messages.

During Anton's appearance, show co-host Brian Kilmeade asked him if Trump has any leverage over Pelosi and Schumer, and he replied the "American people's public opinion" was on his side.