WASHINGTON (AP) — President Donald Trump took to Twitter on Thursday to ratchet up his demands on his long-stalled border wall, appearing to sour on congressional talks aimed at striking a deal with Democrats that he could sign.

In a barrage of morning tweets, Trump sent mixed messages in which he alternately hardened his wall demand, but also suggested that repairing existing fencing is a big part of his plan.

"Lets just call them WALLS from now on and stop playing political games! A WALL is a WALL!," Trump tweeted.

Trump's tweets came a day after Democrats in the House offered a vague border security plan that would not provide a penny for his wall, ignoring — for now — his warnings that they'd be wasting their time if they don't come up with wall money.

The Democratic offer Wednesday was just a starting point in House-Senate talks on border security funding that kicked off in a basement room in the Capitol. A top Democrat acknowledged that "everything is on the table," including the border barriers demanded by Trump. Lawmakers on both sides flashed signs of flexibility, eager to demonstrate willingness to compromise in hopes of resolving the standoff with Trump that sparked the 35-day partial government shutdown.

But Trump on Thursday tamped down expectations, telling GOP negotiators that they were "wasting their time."