TRES VALLES, Mexico » At least 28 bodies have been recovered from a mass grave in Veracruz, an eastern Mexican state plagued by attacks on migrants and drug cartel violence, officials said Wednesday.

The state government said officials found the grave on a ranch outside the town of Tres Valles. It said investigators were still excavating the grave, but did not release any more details. A local newspaper reported that marines found the bodies after spotting vultures on a dirt road.

The area was being guarded by federal and state police forces, while people with missing relatives or friends began arriving at the offices of state authorities in Tres Valles to see if their loved ones were among the victims. Investigators were looking for more bodies on the ranch, which is known as El Diamante.

On Monday, authorities found seven bodies in a grave in the nearby town of Cosamaloapan. Authorities said the victims were all members of one family from Tres Valles.

The Gulf Coast state of Veracruz has suffered years of fighting between the Zetas drug cartel and its rivals. It is also crossed by tens of thousands of Central Americans migrants heading toward the U.S. each year.

Officials have discovered a series of mass graves around Mexico in recent years, several filled with the bodies of migrants slain by the gangs that control profitable migrant-smuggling routes.

One of the largest single mass graves found in Mexico in recent years was discovered in 2010 in Tamaulipas state. It contained the bodies of 72 migrants, whom authorities said were slain by members of the Zetas angry that the victims declined to work for the cartel.