The long-delayed U.S. Capitol Visitor Center should be completed in June 2008, but delays in critical activities threaten to throw the project’s timeline out of whack yet again, a U.S. House panel was told Wednesday.

The 580,000-square-foot underground facility, a $600 million project, is 95 percent complete, acting Architect of the Capitol Stephen Ayers told the House Appropriations Subcommittee on the Legislative Branch. The last two months presented several “slippages,” he said, “but on average, the number of days lost was less than in previous months.”