President Trump on Thursday delivered a pessimistic assessment on the prospects for funding for his long-promised border wall, saying Republicans are “wasting their time” trying to negotiate with Democrats — and he suggested he’ll go it alone.

“Republicans on the Homeland Security Committee are wasting their time,” Trump tweeted a day after Democrats offered no money for a wall during the first day of congressional talks on border security funding.

“Democrats, despite all of the evidence, proof and Caravans coming, are not going to give money to build the DESPERATELY needed WALL,” he said.

“I’ve got you covered. Wall is already being built, I don’t expect much help!” he added.

Last week, Trump signed a three-week deal to reopen the government, giving lawmakers time to try to hash out a deal. He threatened to declare a national emergency to circumvent Congress and use the military to build the wall if they fail to reach a deal he can sign.

Such a move would almost certainly spark legal challenges.

On Wednesday, House Democrats dismissed Trump’s insistence on physical barriers along the US-Mexico border, arguing that security funds would be better spent elsewhere.

Lawmakers from both parties met at the Capitol to open negotiations aimed at resolving the wall standoff that led to a 35-day partial government shutdown — the longest in US history — over Trump’s insistence on $5.7 billion in wall funding.

Republicans angling for compromise have shifted from using the word “wall” in favor of the word “barrier.”

In recent weeks, Trump also had modified his rhetoric, saying he wants “steel slats” along the border rather than the “concrete wall” he had promised Mexico would pay for.

He said he hoped that wording would be more acceptable to Democrats and that, whether it’s called a “barrier,” ”wall,” ”steel slats” — and even “Peaches,” at one point — “whatever you want to call it, it’s all the same.”

But in his tweetstorm Thursday, Trump dropped the semantics.

“Lets just call them WALLS from now on and stop playing political games! A WALL is a WALL!” he declared.

In earlier tweets Thursday, the president also cited a sharp spike in last year’s murder rate in Mexico as he insisted the wall would be erected “one way or the other.”

“Very sadly, Murder cases in Mexico in 2018 rose 33% from 2017, to 33,341. This is a big contributor to the Humanitarian Crises taking place on our Southern Border and then spreading throughout our Country,” he wrote.

“Worse even than Afghanistan. Much caused by DRUGS. Wall is being built!”

In a separate tweet, he said: “Large sections of WALL have already been built with much more either under construction or ready to go.

“Renovation of existing WALLS is also a very big part of the plan to finally, after many decades, properly Secure Our Border. The Wall is getting done one way or the other!” he said.

Despite some additions and replacements to barriers since Trump took office, none of the work was based on the prototypes that he commissioned to fulfill his signature campaign promise, the Washington Post reported.