TIJUANA, Mexico (AP) — US immigration lawyers are telling Central Americans in a caravan of asylum-seekers that travelled 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 travelling as families, on Sunday will test the Trump administration's tough rhetoric criticising 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 US 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 US 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 said in 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. The San Ysidro crossing, which admits about 75,000 people a day into the country, may be unable to take asylum-seekers if it faces too many at once, forcing people to wait in Mexico until it has more room, according to Pete Flores, US Customs and Border Protection's San Diego field office director. Flores said earlier this month that the port can hold about 300 people temporarily. The Border Patrol said "several groups" of people in the caravan have entered the country illegally since Friday by climbing a dilapidated metal fence. It didn't say how many people.