Trump admin live updates: Gov. says 'no need' after Trump directs troops to Portland

President Trump and Ukrainian President Volodymyr Zelenskyy are meeting on the sidelines of the United Nations General Assembly.

Trump called Zelenskyy a "brave man" and said he has "great respect for the fight" Ukrainians are engaged in. Zelenskyy thanked Trump for his efforts to bring an end to the war.

The Ukrainian president said he would speak to Trump on what's happening on the battlefield, how to finish the war and the issue of security guarantees. Zelenskyy called for greater pressure on Russia and said he supports Trump's call for European countries to stop buying Russian oil.

President Trump is calling off a meeting with top congressional Democrats, saying it would not be productive as he believes their government funding proposal is "unserious and ridiculous."

"After reviewing the details of the unserious and ridiculous demands being made by the Minority Radical Left Democrats in return for their Votes to keep our thriving Country open, I have decided that no meeting with their Congressional Leaders could possibly be productive," Trump wrote in a post on his social media platform.

Trump called off the meeting just hours after Democratic leaders Chuck Schumer and Hakeem Jeffries celebrated the meeting confirmation and addressed what they planned to press Trump on during the gathering.

Jeffries' office said he plans on addressing the cancellation at a 2 p.m. news conference.

The development comes as the Sept. 30 funding deadline inches closer with no clear path forward to avoid a shutdown.

-ABC News' Lalee Ibssa

On ABC's "Good Morning America" on Tuesday morning, ahead of President Trump's speech to the United Nations General Assembly, Secretary of State Marco Rubio defended Trump's handling of the ongoing conflicts across the world -- including Russia's invasion into Ukraine and the conflict between Israel and Gaza.

On USAID cuts, when pressed if the administration's decision to severely cut foreign aid and dismantle the agency responsible for administering humanitarian aid and assistance to foreign countries has led to deaths around the world, Rubio pushed back and said the blame should fall on other countries who don't put up enough foreign aid.

"That's ridiculous. They died because England didn't give enough money, or Canada didn't give more or China didn't. Let's blame the other countries that don't do any foreign aid. How about China? It's the second largest economy in the world and they don't give money?" Rubio said.

"I think anybody who tells you that somehow the United States, if we cut a dollar somehow we are responsible for some horrific thing going on in the world, is just not true," he said.

"No one has died because the United States has cut aid, no," Rubio declared. "We are going to continue to do it, but we will do it the right way and in a responsible way. We aren't going to continue to pour billions of dollars out the door of American taxpayer funds for programs that don't work. And in some cases, flat-out corrupt."

-ABC News' Mariam Khan

Trump signed an executive order designating Antifa as a "domestic terrorist organization.”

The order directs federal agencies to "utilize all applicable authorities to investigate, disrupt, and dismantle any and all illegal operations — especially those involving terrorist actions — conducted by Antifa or any person claiming to act on behalf of Antifa."

The order also directs any necessary investigations and prosecutions of "those who fund such operations."

The order that Trump signed describes the organization as one that "recruits, trains, and radicalizes young Americans to engage in this violence and suppression of political activity, then employs elaborate means and mechanisms to shield the identities of its operatives, conceal its funding sources and operations in an effort to frustrate law enforcement, and recruit additional members."

The order also claims that antifa members coordinate with other organizations "for the purpose of spreading, fomenting, and advancing political violence and suppressing lawful political speech."

"This organized effort designed to achieve policy objectives by coercion and intimidation is domestic terrorism," the order said.

It is not immediately clear how the domestic terrorist organization designation would be made for antifa, which is an umbrella description for far-left-leaning militant groups opposing fascists and neo-Nazis. Antifa does not have a publicly known centralized structure or leadership.

-ABC News’ Michelle Stoddart