The remains of three people were found at the Alamo during an archaeological exploration done in preparation for renovations, Texas officials said.

The three bodies, believed to belong to a young adult, infant, and adult, were discovered in the Monks Burial Room and the Nave of Alamo Church, in San Antonio, the Texas General Land Office said in a statement Friday. The on-site tribal monitor was notified, and excavation of the site where the bodies were found was halted.

The remains were found during a restoration plan meant to preserve the 300-year-old structures at the historic Spanish mission, which was built in the 18th century. Officials were hoping to set up equipment to monitor moisture in the building.

Download the NBC News app for breaking news

The Tap Pilam Coahuiltecan Nation sued the Alamo Trust, the state land office and other groups involved in the renovation in September, claiming they had not been able to protect the ancestral remains buried at the site and saying they were excluded from advising on the restoration.

Remains previously were discovered at the Alamo in 1989 and 1995. Nearly 200 people died in the 1836 Battle of the Alamo, including famed American frontiersmen David Crockett and Jim Bowie, although historians believe the human remains from the battle were burned.