Trump says US did not use tear gas on children

US President Donald Trump on Monday said security forces had to use tear gas at the Mexican border because they were "being rushed by some very tough people" but it was not used on children.

Trump was replying to reporters' queries at the White House over US Border Patrol authorities using tear gas at the Mexican border to repel caravans of illegal immigrants trying to enter the United States.

"We didn't. We don't use it (tear gas) on children," he said.

"They had to use because they were being rushed by some very tough people, and they used tear gas. And here's the bottom line: Nobody is coming into our country unless they come in legally," Trump asserted.

Over the past few weeks, Trump has asserted that no foreign nationals would be allowed to enter the country illegally and they would have to come to the US through legal process.

He has deployed several thousand additional forces on the south western border with Mexico to prevent them from entering the country.

The caravan of illegal migrants are mostly from three Latin American countries Honduras, Guatemala and El Salvador. But it also includes people from South Asia including India and Bangladesh, local media reports said.

Trump said he has asked Mexico not to let them cross the border.

"Mexico wants to see if they can get it straightened out. But we've, during certain time, closed the border. They're not coming into the United States. They will not be coming into our country," he said.