Washington, Nov 20 (IANS): US President Donald Trump is expected to grant a new authority to American troops on the Southwest border with Mexico to protect border personnel from migrants if they engage in violence, according to defence officials.

Currently troops do not have any authorities that would allow them to intervene if the Customs and Border Protection (CBP) personnel came under attack unless they need to act in their own self-defence.

The officials told CNN on Monday that the authority would also allow protection of federal property.

There are 5,800 to 5,900 troops assigned to the border mission.

The mission would be characterised solely as "protection of CBP" personnel, according to the officials.

Monday's development comes as Department of Homeland Security (DHS) officials said earlier in the day that they had started to get information from "multiple sources including individuals in the Mexican government" of potential waves or groups of individuals who were discussing an incursion into legal ports of entry in California by attempting to pass through vehicle lanes.

The Pentagon has been working for the last several days on options for how troops can protect CBP.

More than 2,000 Central American migrants arrived in the border city of Tijuana in recent days, and about 3,000 more migrants were estimated to be in Mexicali, Mexico, another border city about 100 miles away, a UN High Commissioner for Refugees spokeswoman told CNN.