TIJUANA, Mexico — U.S. immigration lawyers are telling Central Americans in a caravan of asylum-seekers that traveled through Mexico to the border with San Diego that they face possible separation from their children and detention for many months. They say they want to prepare them for the worst possible outcome.

“We are the bearers of horrible news,” Los Angeles lawyer Nora Phillips said during a break from legal workshops for the migrants at three Tijuana locations where about 20 lawyers gave free information and advice. “That’s what good attorneys are for.”

The Central Americans, many traveling as families, on Sunday will test the Trump administration’s tough rhetoric criticizing the caravan when the migrants begin seeking asylum by turning themselves in to border inspectors at San Diego’s San Ysidro border crossing, the nation’s busiest.

President Donald Trump and members of his Cabinet have been tracking the caravan, calling it a threat to the U.S. since it started March 25 in the Mexican city of Tapachula, near the Guatemala border. They have promised a stern, swift response.

Attorney General Jeff Sessions called the caravan “a deliberate attempt to undermine our laws and overwhelm our system,” pledging to send more immigration judges to the border to resolve cases if needed.

Homeland Security Secretary Kirstjen Nielsen said asylum claims will be resolved “efficiently and expeditiously” but said the asylum-seekers should seek it in the first safe country they reach, including Mexico.

Any asylum seekers making false claims to U.S. authorities could be prosecuted as could anyone who assists or coaches immigrants on making false claims, Nielsen said.  Administration officials and their allies claim asylum fraud is growing and that many who seek it are coached on how to do so.

Kenia Elizabeth Avila, 35, appeared shaken after the volunteer attorneys told her Friday that temperatures may be cold in temporary holding cells and that she could be separated from her three children, ages 10, 9 and 4.

But she in said an interview that returning to her native El Salvador would be worse. She fled for reasons she declined to discuss.

“If they’re going to separate us for a few days, that’s better than getting myself killed in my country,” she said.

Since Congress failed to agree on a broad immigration package in February, administration officials have made it a legislative priority to end what they call “legal loopholes” and “catch-and-release” policies that allow asylum-seekers to be released from custody while their claims wind through the courts in cases that can last for year.