US Border Patrol agents chasing suspected drug traffickers on the Texas border allegedly crossed into Mexico and had a brief standoff with Mexican police officers. No shots were fired, a Mexican official said Friday. Jose Luis Delgado, an officer in the town of Guadalupe, 40 kilometers southeast of Ciudad Juarez - across from El Paso, Texas - said he and two officers were responding Thursday afternoon to a report that a pickup truck loaded with marijuana had been abandoned in the Rio Grande when they encountered several US Border Patrol agents on Mexican territory. Delgado said he and the officers arrived with their weapons drawn. "When we arrived (the US officials) drew their weapons," Delgado said in a telephone interview. Delgado said 20 or 25 US Border Patrol officers "wearing green uniforms" had formed a human chain along a shallow area of the river and were unloading the packages from the vehicle when he identified himself as a police officer and asked them to leave Mexican territory. The US officials returned to the US side of the border and a few remained there until Mexican officials towed the car, Delgado said. "They even asked us to turn the car over to them but I said no," Delgado said. Rogelio Garcia, a spokesman with the US Border Patrol El Paso sector, confirmed that US agents seized about 140 kilograms of marijuana from a pickup truck that at least two suspected drug traffickers abandoned in the river before running into Mexico. Garcia said he couldn't confirm whether the pickup truck was on the Mexican side of the border because the matter "is still being investigated." Garcia said US agents began chasing the pickup truck fitted with a camper shell in Fort Hancock, Texas, when the driver crossed the river into Mexico about five kilometers (three miles) west of the Fabens port of entry. Garcia said the area, where the river is about half-a-meter deep, is commonly used by drug traffickers. Rene Medrano, a spokesman for the state attorney general's office in Chihuahua, where Guadalupe is located, said state investigators seized 655 kilograms of marijuana from the 2005 Chevrolet pickup truck, reported stolen in El Paso. He said the truck was stuck in mud about 35 meters from the banks of the Mexican side of the river. Medrano said he couldn't corroborate the alleged incursion of US agents into Mexico because "when state officials arrived, US Border Patrol agents were on the US side." Medrano said the case has been turned over to federal officials.