More than 70 migrants from Central America have now crossed into the United States to formally request asylum. They're part of a larger group determined to cross the Mexico-US border. Nearly 200 arrived Sunday. CGTN's Alasdair Baverstock reports on their plight-- and a group of angels who are trying to help them.

As the Central American migrant caravan languishes at the US border, uncertainty remains the overwhelming factor.

The first small group of migrants was ushered through to plead for U.S. asylum Monday night, and others have followed. But for those who remain, no one can say how long the wait might be.

But support is at hand, from a concerned group of San Diego volunteers, called the Border Angels.

JORGE SANCHEZ MEMBER, BORDER ANGELS "So I have the opportunity to come by, drop off things, and cross the border safely, you know, so I feel like I have the responsibility to do so. Also in solidarity, I'd rather be here at least one night, or maybe two, or however long I can be instead of staying at home and watching it on TV."

Since 1998, the Border Angels have taken an active role in helping illegal migrants on their journeys to cross the border.

The group became well-known for its delivery of what can be life-saving supplies jugs of water, packs of food, left at points in the open desert known to be frequented by illegal crossers.

They are led by Enrique Morones.

ENRIQUE MORONES FOUNDER, BORDER ANGELS "The way that we have been helping them is that we give donations for them, to be there, to be prepared with blankets and supplies that they might need, and we have also had members of the border angels join them at certain points, and we have also contributed financially as well."

Despite this show of support from some American citizens, immigration attorneys in San Diego, across the border from Tijuana, hold out little hope that the migrant caravan can remain in the US, even if they are initially allowed in.

JAMES RUDOLPH SAN DIEGO IMMIGRATION ATTORNEY "So their chances of their winning the asylum, in my opinion, are low, very very low. They still get to see an immigration judge, and a lot of them will stay detained, and it can take six months to a year for the asylum process to play out."

Those who remain say going back to Central America, and the violence that drove them out, is not an option.

ALASDAIR BAVERSTOCK SAN DIEGO, CALIFORNIA After four days at the border, some members of the caravan have accepted the Mexican authorities' offer of migrant shelter housing in Tijuana. So the caravan's unity - its strength in numbers which got them this far, has fractured somewhat. The question now is what impact this will have on those who remain, determined to seek US asylum. Alasdair Baverstock, CGTN, at the US-Mexico border.