On April 25, 1846, Captain Seth B. Thornton received reports of Mexican troops crossing the Rio Grande. Thornton and 63 U.S. dragoons moved to Rancho de Carricitos and discovered several houses in the area. Mexican General Anastasio Torrejón crossed the Rio Grande the previous day. He commanded 1,600 cavalry and infantry troops to surround Thornton's troops in fractions. Due to heavy force from Torrejón's troops, Thornton's troops surrendered. Eleven American casualties were reported; 45 troops and Thornton were held as prisoners. Reports of the incident were sent to President James K. Polk, who announced, "American blood has been spilled upon the American territory". On May 13, the United States Congress declared war against Mexico.