A mother-of-two was impaled after she tried to scale a US-Mexico border fence in San Diego on Friday night.

According to US Border Patrol, the 26-year-old woman from Guatemala was with her two children, aged three and five, when she climbed the fence near the San Ysidro Port of Entry.

The San Diego Union-Tribune reported that she climbed a fence east of the port and where construction crews were putting up a new barrier to replace the old fencing.

The mother lost her balance and fell, and pieces of rebar pierced her side and buttocks.

A 26-year-old mother of two was impaled by pieces of rebar as she attempted to scale a fence on the US-Mexico border wall on Friday night. Pictured: US Marines deploy concertina wire at the border in preparation for the arrival of a caravan of migrants at the San Ysidro border

Border Patrol told the Union-Tribune that it was dispatched to give medical aid around 8.30pm and asked for help from the San Diego Fire Department.

The woman was taken to the hospital by paramedics with non-life threatening injuries.

Her children were also evaluated for trauma and, when they were cleared, were released to the custody of Border Patrol.

No information was available on whether the woman was planning to claim asylum in the US.

Border Patrol Agent Eduardo Olmos told City News Service that the woman told agents she was not part of the migrant caravan that arrived in Tijuana last week.

'Entering our country illegally, particularly over our walls is not only dangerous, but also very foolish,' San Diego's Chief Border Patrol Agent Rodney Scott said on Saturday.

'This woman placed her own life and her children's lives in peril. She could have easily died if not for the quick response by our agents and EMS.'

Officials say the rebar was part of ongoing construction and not related to the US military's recent mission to fortify the fence from the caravan.

Border Patrol Agent Eduardo Olmos told City News Service that the woman told agents she was not part of the migrant caravan that arrived in Tijuana last week. Pictured above, an aerial view of the temporary shelter set up for members of the caravan in Tijuana

Seven-year-old Honduran migrant Genesis Belen Mejia Flores waves an American flag at U.S. border control helicopters flying overhead near the Benito Juarez Sports Center serving as a temporary shelter for Central American migrants, in Tijuana, Mexico

According to the Union-Tribune, the fortification has primarily involved stringing concertina wire at the top of the fence.

As of this weekend, about 5,000 migrants are in Tijuana waiting to enter the US with most of them planning to claim asylum.

Mexico's incoming government has agreed to back the Trump administration's plan to change US border policy by requiring asylum seekers to wait in Mexico while their claims move through US courts, the Washington Post reported on Saturday.

Citing Mexican officials and senior members of president-elect Andres Manuel Lopez Obrador's transition team, the newspaper said the agreement would break with long-standing asylum rules and mount a new obstacle to Central American migrants attempting to reach the US and escape poverty and violence.

The paper said that, according to the outlines of the plan, asylum applicants at the border will have to stay in Mexico while their cases are processed, potentially ending the system President Donald Trump decries as 'catch and release' that has until now generally allowed those seeking refuge to wait on safer US soil.

Trump has been seeking to block thousands of Central Americans traveling in caravans from entering the US and has ordered that immigrants who enter the country illegally from Mexico are ineligible for asylum.

That order has been temporary suspended by a US judge.