In a primetime television address to the nation Tuesday night, President Donald Trump called for support for his long-promised border wall - an issue that has prompted the partial shutdown of the federal government - but he stopped short of declaring a national emergency at the border with Mexico.

Speaking from the Oval Office, Trump explained why he views the situation at the Mexico border as a "growing humanitarian and security crisis," and has said he wouldn't sign any government funding bill that does not include money for the border wall.

Trump claimed illegal drugs are flooding across the border and related stories of crime by illegal aliens and of human trafficking. The situation is "a crisis of the heart, and a crisis of the soul," he said.

The president said his administration's proposal includes new technology, improved border security, and increase personnel. It also includes $5.7 billion for the physical barrier -- "a steel barrier rather than a concrete wall," Trump said.

He said he has invited congressional leadership to the White House on Wednesday to negotiate a deal for border security and which would end the government shutdown.

The address comes as the partial shutdown, heading into its third week is days from becoming the longest in U.S. history.

The president had earlier indicated he might declare a national emergency to get the military to start work on the border wall, but lawmakers in both parties signaled they would not support that move. On Tuesday, according to a published report in the online edition of the Wall Street Journal, Rep. Mac Thornberry, R-Texas, the top Republican on the House Armed Services Committee, told reporters he opposed using an emergency declaration to build a wall using military funds.

In the meantime, the effects of the now 18-day shutdown are growing. The National Pilots Union has called for reopening the government on the grounds of air safety. Government workers will likely miss their first paycheck this Friday, acting White House Chief of Staff Mick Mulvaney said. If the shutdown lasts a month, some estimate show quarterly annualized growth could slow by 1.5-2 percentage points, according to the Committee for a Responsible Federal Budget.

It's unclear whether Trump is feeling any pressure to end the shutdown, which he said earlier might last for months, or even years. Still, after his speech, he may believe he's promoted his wall enough and find a way to deflect some of the criticism he's received.

"In a private meeting with aides at Camp David on Sunday," the Journal reported, "Mr. Trump said he wanted them to come up with a resolution to the shutdown fight that would reopen the government without him appearing to have capitulated to Democrats, a person familiar with the meeting said."

Markets showed little immediate reaction to the speech. U.S. stock futures were higher, following up on Tuesday's gains during the regular session. Dow futures rose 0.5%, while those for the Nasdaq were up about 0.6%.  

In Tokyo, the Nikkei 225 was up 1.24%.