Mexican navy officials said Tuesday that one marine was killed and two others wounded in an ambush by drug cartel gunmen in the State of Mexico, just west of Mexico City.

The ambush, and the earlier discovery of an opium poppy plantation in a nearby town, suggested that drug cartel violence may be moving ever closer to the nation's capital.

The marines were on patrol in the township of Luvianos when gunmen opened fire on the troops in the main square of an outlying hamlet from the roof of a building and from a moving vehicle.

The two wounded marines are in stable condition.

While shootouts with police are not uncommon in Mexico City, ambushes of military patrols are rare so close to the capital. The scene of the shootout was about 120 kilometers (100 miles) west of Mexico City.

Earlier, the navy said marines found and destroyed a 6-acre (2.4-hectare) opium poppy plantation even closer to the capital. The field was found in the State of Mexico about 80 kilometers (50 miles) from Mexico City, near the Nevado de Toluca volcano.

The navy said in a statement late Monday that it found the field over the weekend, after receiving tips that a gang was guarding drug plots in the area. It said an estimated 221,000 poppy plants were destroyed in the raid.

Poppy plantations in Mexico are usually smaller plots located in the remote mountains of Guerrero state in the south or the mountains of Chihuahua, Sinaloa and Durango states in the north.

It is unusual to find such a large plot so close to the capital. The navy did not say what gang or drug cartel was suspected of planting the poppies, but said a campsite was found nearby.