Mexico City (CNN) The first migrants from a caravan that sparked the ire of President Donald Trump have started arriving at the US-Mexico border and asking for asylum, advocates say.

About 50 Central Americans have arrived in Tijuana, Mexico, according to Juventud 2000, an organization that assists migrants in that border city.

Of those, about 10 have turned themselves in to US authorities at the border. Others are waiting for a larger contingent from the caravan to arrive before they head north, Juventud 2000 Director Jose Maria Garcia Lara said.

There are many questions looming about the group's next steps. Chief among them: What will happen once larger numbers reach the border?

Many of the migrants say they're fleeing violence and poverty in Central America. They're part of a caravan that convened at Mexico's southern border weeks ago, then trekked through the country as part of an annual pilgrimage organized to bring light to migrants' plights.

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