A high-level Russian diplomat was questioned by local and federal authorities Sunday after a 911 caller became suspicious of a man photographing a liquefied natural gas terminal on the waterfront in Calvert County, Maryland State Police said.

"It seems to be very innocent," said Lt. Homer Rich, adding that the man appeared to be taking pictures of the bay, various wildlife and fauna with the gas terminal in the background.

Calvert residents and Maryland lawmakers have raised concerns that the liquid nitrogen gas facility could become a target of terrorist attack. Specifically, they have said that allowing foreign tankers into the bay could make the area vulnerable to an attack that could engulf the nearby Calvert Cliffs Nuclear Power Plant.

On Sunday, a state trooper, responding to a call by a person reporting suspicious activity, found a man videotaping and photographing about 5 p.m. near the Dominion's Cove Point gas terminal in southern Calvert County, Rich said.

The man, whom authorities identified only as a member of the Russian Embassy who has been living in the United States for six years, was not detained, Rich said.

The man's digital camera card and videotape were confiscated by Trooper David Whipp and will be forwarded to the State Department or the Department of Homeland Security, Rich said. If federal authorities find the items not to be a threat, they will be returned to the man, he said.

"It does not appear to be that he was focusing on the power plant," Rich said, adding that the man was not trespassing when he got out of a vehicle and took the pictures and video.

"We're going on the premise that he was just a person taking photos of nice things in Calvert County."

Authorities are nevertheless taking the matter seriously because law enforcement officials all over the region are sensitive to people snapping pictures of facilities considered potential terrorist targets.

Rich said that after reviewing the pictures and videos, investigators determined that there "was nothing of great worthiness" but will send the items to federal authorities. "It's good to be careful," he said.

Rich said the man appreciated the gravity of the situation when he turned over his digital card and videotape. "He understands why we're taking this action."

Yevgeny V. Khorishko, press secretary for the Russian Embassy in Washington, declined to provide the name of the man, but confirmed that he was a high-ranking diplomat on the embassy staff. Khorishko said the man could have invoked diplomatic immunity to retain his camera equipment but opted to cooperate with authorities because he understood their concern over security at the facility.