WASHINGTON, Oct. 29 (CGTN) -- The Pentagon is deploying 5,200 active-duty troops to beef up security along the US-Mexico border, officials announced Monday, in a bid to prevent a caravan of Central American migrants from illegally crossing the frontier.

The move represents a massive military buildup along the border, where some 2,000 National Guardsmen are already working to assist the overwhelmed authorities.

Trump in recent weeks has repeatedly said more troops are needed to tighten border security, and he has made political capital of the caravan ahead of crucial midterm congressional elections that could see the Democrats regain some degree of power.

According to US Customs and Border Protection Commissioner Kevin McAleenan, US authorities are tracking a group of about 3,500 people traveling north through the Chiapas-Oaxaca area in southern Mexico.