It was supposed to be a festive day of celebration Saturday, Dec. 5, when Nuevo Progreso, just across the border and a little south of McAllen, hosted their annual "Welcome Back" party for winter visitors to the Valley and the region. The small Mexican ranching community is known for its hospitality and peaceful shopping setting - a place where finding a dentist or health clinic is easy and visiting a pharmacy for prescription drugs is standard. Drug violence is something that happens in other, larger Mexican border towns, and the popularity of Nuevo Progreso hinges on that reputation. But unexpected gunfire sent hundreds of Winter Texans scrambling from cover on Saturday as drug violence broke out on the crowded streets about a block away from the festival, a rattling experience for many winter visitors who had just recently arrived in the Valley for their annual stay. It all happened about 2 p.m. Saturday afternoon. After hundreds, perhaps thousands of visitors walked across the Nuevo Progreso bridge and joined the festivities on a blocked off street where the event is held each year, a truck crashed into a building about a block away and gunfire erupted sending Winter Texans and locals alike looking for cover. Mexican military soldiers began exchanging fire with what were described as Zeta drug cartel members moments after the car crashed through the door of a local bar. When the smoke cleared and the gunfire stopped, a mass exodus of winter visitors streamed back across the bridge, many to find the bridge had been closed to all traffic in both directions for at least three hours, stranding them in an uncomfortable and frightening nightmare of potential violence and personal threat that few will ever forget. The Mexican military is still being vague about the incident, saying only it involved drug troops and cartel members. There has been no official word on the extent of injuries suffered by those involved in the shooting. Mexican officials say the incident is still under investigation. But Mexican news reports indicate at least two people were killed and others were wounded. Meanwhile, the streets in Nuevo Progreso were ghostly quiet for the remainder of the weekend, a ghost town-looking scene in Progreso's busiest tourist district. Mexican business owners say they fear the visitor's may not come back, and a few Winter Texans commented after the incident they were uncertain whether they would return this season. Edgar Marshall and wife Donna of Iowa Falls, Iowa, were in nearby Port Isabel Saturday to watch the lighted boat parade and say they were planning on visiting Progreso Sunday until they heard about the news. “We almost went to Progreso today,” said Edgar Marshall pointing to the boats lining up at White Sands Marina. “But the wife didn't want to miss this parade. We usually take in the parade every year, but we cross over (to Progreso) at least a couple of times during our stay to pick up medicines. I'm not sure if we're going over this now after what happened.” "They carried a man, who was shot, out of there — there were two Mexicans carrying him. And out of nowhere, some soldiers materialized, and made them put him down. And they trained their weapons on him and were asking questions. They were wanting to know whether he was a bad guy, I assume, " says Ron and Carol Watson, who are from Avonlea, Canada, a Winter Texan who travels south each year with his wife Carol. Watson says he and his wife were separated at the time the gunfire erupted. He took shelter in a restaurant where the owner advised him to lay on the floor. His wife Carol was shopping in a store about a block away. Neither of the Americans were injured, but others reported seeing bodies in the streets and soldiers questioning "everyone in sight" once the bullets stopped firing. Not far from where the Winter Texan event was staged and from where the trouble started, a Christian Mission group from Minnesota had just arrived in town. The group had been working on the Texas-Mexico border for about three weeks, building soup kitchens in nearby Matamoros and providing food and clothing for many of the poverty-stricken Mexicans living in the border towns. With all their mission work completed, the men were in town for souvenirs and lunch. That's when they first heard the shots, what they thought at first were fireworks going off. They noticed that as the people around town were walking and milling about, they were all looking in the same direction — the direction of the gunshots. About a block and a half down from where they started, they became a little more cautious and started moving a little more slowly. They could see a white pickup truck moving toward them, driving very slowly. Then they realized that what they were seeing were guns being fired out of the truck. The group agreed that it seemed surreal, like they were watching a movie. “The reason is because it was business as usual. There were no people running or screaming,” said one of the mission workers. As they watched the truck make its way slowly down the street, they realized that more shots were being fired, but that those shots were coming from the north and that it was the military or border police firing back at the truck. One of the shots hit the driver of the truck and the truck then veered off the road and into a pole, stopping dead in its tracks. At that point, the men all took cover. “We just dove into wherever we could find that looked safe,” said the mission volunteer, adding that seven of them went into one shop, one went into another and the last four went a different direction. After the truck hit the pole, there was a slight pause or cease in shots being fired, the group explained. But then, after they had all taken cover, within a matter of seconds, there was a barrage of shots fired over and over again. Another Winter visitor, identity unknown, said he started taking video footage of what he thought was an auto accident. But a few moments, he too heard the gunfire and back-peddled down the street, stumbling over a body. The man on  the ground had been shot. He tried to help but said Mexican soldiers rushed in and forced him to stop, thinking the body might have been that of a cartel operative. Virginia Canales lives in Oklahoma City and says she and sister Theresa were visiting family in the Valley and decided to cross over into Nuevo Progreso to visit a pharmacy. "We were just wanting to get medications cheaper than what they cost back home. We were not there to party or to linger. We had just bought the prescriptions and were headed back to the bridge when a military truck whizzed by and got the bridge and unloaded. They weren't letting anyone back across to Texas," she reports. Merchants in the small Mexican village say the weekend's event was the last thing they needed after months of troubled economic times. With Winter Texan season arriving, they say they had hope that they might finish the year on a positive note. "Now we are afraid the people won't come back across the border." says Miguel Allenda, a shop owner in town. "If the tourist stay away, we might as well close the doors." Travelers across the border are warned to take care and be aware of the dangers. Not every visitor faces such threatening incidents. Most, in fact, do not. But the incident serves as a reminder that border violence is very real and can happen anywhere - fast.