Updated

The government will begin taking land from seven property owners so that the Flight 93 memorial can be built in time for the 10th anniversary of the 2001 terrorist attacks, the National Park Service said.

In a a statement obtained by The Associated Press, the park service said it had teamed up with a group representing the victims' families to work with landowners since before 2005 to acquire the land.

"But with few exceptions, these negotiations have been unsuccessful," said the statement, which was to be released later Thursday.

The seven property owners own about 500 acres still needed for what will ultimately be a $58 million, 2,200-acre permanent memorial and national park at the crash site near Shanksville, about 60 miles southeast of Pittsburgh.

"We always prefer to get that land from a willing seller. And sometimes you can just not come to an agreement on certain things," park service spokesman Phil Sheridan said.

Two owners account for about 420 acres the park service plans to condemn, including Svonavec Inc. — which owns 275 acres, including the impact site where 40 passengers and crew died. About 150 acres are owned by a family that operates a scrap yard.

Most of rest of the land to be condemned are small parcels, two of which include cabins.

"It's absolutely a surprise. I'm shocked by it. I'm disappointed by it," said Tim Lambert, who owns nearly 164 acres that his grandfather bought in the 1930s. The park service plans to condemn two parcels totaling about five acres — land, he said, he had always intended to donate for the memorial.

"To the best of my knowledge and my lawyer, absolutely no negotiations have taken place with the park service where we've sat down and discussed this," Lambert said.

Lambert said he had mainly dealt with the Families of Flight 93 and said he's provided the group all the information it's asked for, including an appraisal.

While he knew that condemnation was a possibility, he thought it was an unlikely scenario and that the park service and family group had wanted to acquire the larger parcels before dealing with owners of smaller properties.

"I was never told that May was the drop-deadline," he said.

In February, government officials and representatives of the 33 passengers and seven crew members killed when the plane crashed on Sept. 11, 2001, pledged to dedicate a memorial on the site by the 10th anniversary. Officials said then that more than 80 percent of the needed land had been secured.

United Flight 93 was traveling from Newark, N.J., to San Francisco when it was diverted by hijackers with the likely goal of crashing it into the White House or Capitol. The official 9/11 Commission report said the hijackers crashed the plane as passengers tried to wrest control of the cockpit.