A migrant woman, part of a caravan of thousands traveling from Central America en route to the United States, tries to get off from the back of a truck while making their way to Tijuana from Mexicali, in Mexicali, Mexico, Nov. 20, 2018. (Xinhua/REUTERS)

WASHINGTON, Nov. 22 (Xinhua) -- U.S. President Donald Trump renewed a threat on Thursday to shut down the entire U.S. border with Mexico as part of his administration's efforts to deter the entry of Central American migrants.

"If we find that it gets to a level where we are going to lose control or where people are going to start getting hurt, we will close entry into the country for a period of time until we can get it under control," Trump told reporters in Palm Beach, Florida, where he is spending the Thanksgiving holiday weekend.

"I mean the whole border," he said. "Mexico will not be able to sell their cars into the United States where they make so many cars."

A group of migrants, many of whom say they are fleeing persecution, poverty and violence in Honduras, Guatemala, and El Salvador, are making their way through Central America towards the U.S. border for weeks. Many of them want to claim asylum.

More than 1,000 migrants have arrived in the Mexican border city of Tijuana, according to reports.

Thousands of U.S. troops have been deployed along the country's southern border with Mexico to help strengthen border security while offering only engineering, logistic and medical support.

However, Trump said Thursday that he has given the troops the "OK" to use lethal force against migrants "if they have to."

Meanwhile, the president would not discount the possibility of a partial government shutdown early next month over Congress' refusal to authorize the funding that he's asking for a border wall, the central promise of his 2016 presidential campaign.

"Could there be a shutdown? There certainly could, and it will be about border security, of which the wall is a part," he said.

Trump made the comments when answering questions by reporters at his Florida golf club after he conveyed holiday wishes in a telephone call with U.S. service members.

He also talked about his public dispute with Chief Justice John Roberts, a possible staff and Cabinet shake-up and the U.S. economy, among other things.