Members of a caravan of Central American migrants that has prompted abrasive tweets from President Donald Trump may attempt to apply for asylum at the Nogales Port of Entry, an organizer said Wednesday.

It’s unclear how many of them or when will travel to the border. The group — more than 1,000 people, many of them Hondurans who say they’re fleeing violence in their country — is expected to end its collective journey once they reach Mexico’s capital next week, said Gina Garibo, one of the group’s organizers.

Some will likely continue and seek to apply for asylum in Nogales, Calexico or San Diego, Garibo said.

The caravan has become a political lightning rod between the United States and Mexico. Trump issued warnings about the group this week, and tweeted that he would send troops to guard the border. In response, Mexico’s Senate approved a measure on Wednesday, calling on the government to cease collaborating with American authorities on issues of immigration anti-drug trafficking.

“It’s a shame that Trump is targeting us,” Garibo said in an interview. “If the military comes to the border to meet us, they will find mothers holding their children.”

The caravan had set off on foot in the city of Tapachula, near Mexico’s border with Guatemala, last week. On Wednesday, they were still in the southern state of Oaxaca, at least 300 miles from the closest crossing to the United States. Mexican immigration officials gave legal permits of up to a month to many of them, Garibo said.

Caravans such as this one have been commonplace for years, as a way for migrant advocates to raise awareness. They occur apart from the regular flow of migrants and are discouraged by many humanitarian workers. Trump’s tweets brought attention to this year’s caravan.