Suspected drug gang gunmen shot it out with Mexican soldiers and policemen in a Monday clash that left three gunmen dead in what was once a quiet border town, according to press service accounts. The attack came in Rio Bravo, across the border from McAllen, Texas, where the November killing of a local politician by suspected drug cartel hit men led President Felipe Calderón to call in the army, sending in 3,000 troops to occupy the town last month.

According to witness and official accounts, a group of about 20 armed men confronted a unit of soldiers after they had searched a suspected safe house. The gunmen attacked with grenades, sparking a fierce gun battle that also left 10 police and soldiers wounded and 10 people under arrest.

The New York Times had a slightly different account. According to the Times, the fighting broke out when federal agents tried to stop a van with three men visibly carrying arms. The men then retreated to a nearby house to joint their comrades, and engaged soldiers and police with rocket propelled grenade launchers.

Also according to the Times, citing Mexican officials, three of the 10 people arrested were US citizens, one from Texas and two from Detroit.

"The aggressors threw dozens of grenades and there was a lot of blood on the street. Some civilians were badly hurt and taken to hospital," local journalist Ely Enríquez told Reuters.

In Mexico's drug war, northeast Mexico is the home turf of the Gulf Cartel, one of the violent Mexican drug trafficking organizations getting rich off prohibition and killing competitors, cops, and soldiers if they get in their way. The Gulf Cartel is especially notorious for its armed enforcers, the Zetas, composed of former elite Mexican anti-drug soldiers.

On Tuesday, the Zetas struck back, a few dozen miles up the Rio Grande River at Reynosa. That evening, gun men attacked military and police patrols in the city center, killing three agents in a hail of gunfire and RPGs. As a local press account noted, "Witnesses reported seeing several explosions near the scene Tuesday night, including one grenade that detonated next to a truck in a church parking lot. Blood stains, charred body armor and helmets littered the streets surrounding the crime scene.

Last year, a record 2,500 or so people died in Mexico's drug wars. This year, it looks like we're in for more of the same, even though Mexico City and Washington are busy hatching a billion dollar-plus anti-drug assistance package.