美国有线新闻 CNN 非法越境人数爆增 特朗普在美墨边境部署警卫队（在线收听）

And we're starting this Monday with a follow-up on a story we brought you last week. We reported that U.S. President Donald Trump was sending a number of National Guard soldiers to the border between America and Mexico. Now, we know that number, the president wants to deploy between 2,000 and 4,000 guardsmen there. And the order from Defense Secretary James Mattis is for up to 4,000 National Guard personnel to go and they're scheduled to be there through the end of September.

President Trump says this will help seal off America's southern border, providing better security and safety for Americans. Critics of previous deployments like this say they were costly and limited in terms of how effective they were. The border between the U.S. and Mexico is 1,954 miles long. It runs from the Pacific Ocean to the Gulf of Mexico and while most of that border, more than 1,200 miles of it, runs along the U.S. state of Texas, the barriers that are currently there cover 100 miles.

The National Guard has been deployed along the border before. Six thousand soldiers were sent by former President George W. Bush, beginning in 2006.

Twelve hundred soldiers were sent by former President Barack Obama beginning in 2010. And this year, President Trump is planning to deploy guardsmen to the border until his proposed wall is completed.

President Bush signed what was called the Secure Fence Act back in 2006. What that did was authorized more barriers and surveillance equipment at the border. Ten years after that, in 2016, there are around 700 miles of fence along the border. It's different heights at different places, the tallest parts being 18 feet off the ground.

As far as apprehensions at the border are concerned, the government says almost 304,000 people were arrested or detained for illegally crossing the border in the 2017 fiscal year.

NICK WATT, CNN CORRESPONDENT: Here in Arizona, we are told that National Guard planners are working over the weekend in advance of the deployment of 150 personnel sometime during next week. Exactly where they will be stationed, we do not know and exactly when they will be deployed, we also do not yet know. Over in Texas, of course, the deployment has already begun.

Now, is this even necessary? Well, opponents will point to the stat back in 2000, 1.6 million people were apprehended on the southwest border and that has fallen to around 300,000 a year. Proponents will say, yes, but this march is up on March 2017, and march was up on February and they will say that more families and more individuals are crossing the border and that is why the Department of Homeland Security is calling what's happening on this border right now a crisis.

Nick Watt, CNN, Nogales, Arizona.