TIJUANA, Mexico _ As a cold rain fell in Tijuana, a group of Central Americans faced off with Mexican police sent to block them from launching a hunger strike near the U.S. border.
Leading the migrants were activists from the group Pueblo Sin Fronteras, or People Without Borders.
The small collective of volunteers based in the U.S. and Mexico helped create the migrant caravan trend; it organized the first caravan to the U.S. border last year and has helped guide the groups now in Tijuana.
It says the caravans help protect migrants from rape, kidnapping and other perils while drawing attention to the reasons they flee and their treatment on the journey north.
But Pueblo Sin Fronteras has drawn considerable criticism. Conservatives accuse the group of human trafficking. And some former allies on the left say it is using migrants to advance its political agenda _ imperiling the people it claims to protect.
"They are helping Donald Trump say there is an invasion," said Alejandro Solalinde, a Catholic priest and one of Mexico's most prominent migrant activists.
Solalinde believes the caravan strategy has backfired, with images of migrants streaming north and scaling border walls helping President Donald Trump justify harsher immigration enforcement, including sending thousands of U.S. troops to the border.
"Pueblo Sin Fronteras cheated the migrants; they told them lies that once they arrived at the border, everything would be very easy," Solalinde said.
Instead, roughly 6,000 migrants have been left stranded in this sprawling industrial city _ with most living off handouts from volunteer groups in government-run shelters _ as U.S. officials at the border generally accept no more than 100 asylum applications each day.
Pueblo Sin Fronteras insists that migrants have decided for themselves where to travel and when to protest, and that it simply "accompanies" those who have already decided to try to reach the United States.
Yet it has frequently taken a more active role. In October, activists with the group ferried immigrants illegally from Guatemala into Mexico, and they have repeatedly led migrants into direct confrontations with law enforcement.
Last week's rain-soaked altercation in Tijuana began when several members of Pueblo Sin Fronteras marched with a few dozen migrants, including children, toward the border to launch a hunger strike. When police in riot gear tried to stop them, Irineo Mujica, the director of Pueblo Sin Fronteras, escalated an already tense situation.
"You're going to tell us where we can demonstrate?" Mujica shouted as the migrants stood behind him. "It's our right to protest!"
Eventually, police let the migrants pass. Several members of Pueblo Sin Fronteras have joined them in the weeklong hunger strike, which seeks to pressure the U.S. to speed up its intake of asylum applicants.
Another march in Tijuana led in part by Pueblo Sin Fronteras turned violent last month after some migrants pushed past Mexican police and sought to scale a border fence into San Diego. Several migrants were injured when U.S. authorities responded with rubber bullets and tear gas.
Alex Mensing, a Pueblo Sin Fronteras activist who was at the protest, said he tried to persuade migrants to not storm the border.
He said the group has been transparent about what migrants should expect.
"We have done everything we possibly can to inform people," he said, adding that he gave migrants know-your-rights training about asylum law as they hitchhiked on 18-wheeler trucks up through Mexico last month.
"We can't force people to listen," Mensing said. "We never promised anybody anything other than that we would walk with them."
