BISMARCK, N.D. (AP) — Federal authorities reviewing a Chinese company’s purchase of land in North Dakota for a wet corn milling plant say more information is needed before they can decide whether the project might be detrimental to national security.

Fufeng Group’s planned $700 million project in Grand Forks is near a U.S. Air Force base, prompting opponents to raise concerns about potential for espionage.

The Committee on Foreign Investment in the United States told Fufeng in a letter this week that the information the company has provided is “insufficient.” The company said in a statement that it has been “open and cooperative” with U.S. officials and will comply with the government’s request for more information.

Grand Forks City Administrator Todd Feland said Friday that infrastructure work being done by the city for the project would be halted until the review is complete. He said the review is expected to take up to three months.

“I think it’s going to be one of the most highly scrutinized projects from a national security perspective through this process, which is good for everybody,” Feland said.

Amid growing opposition toward the project, Gov. Doug Burgum, and North Dakota U.S. Sens. John Hoeven and Kevin Cramer — all Republicans — pressed the U.S. government in July to expedite a review to ensure it doesn’t pose a risk to national security.

The Grand Forks City Council in February gave initial approval to the Chinese agribusiness for its proposed corn-milling facility that officials said could be the largest private sector investment in the community’s history.

Fufeng makes products for the animal nutrition, food and beverage, pharmaceutical, health and wellness, oil and gas, and other industries. It’s a leading producer of xanthan gum. The Grand Forks site would be its first U.S.-based manufacturing facility.