University President Drew G. Faust announced Wednesday afternoon that Harvard will slow construction on the Allston Science Complex for the rest of 2009, as the University reassesses its financial situation after an unprecedented decline in its endowment.

The news follows months of warnings that the economic downturn could delay Harvard’s ambitious plans for a new campus across the river. Harvard has heralded the Science Complex as a core part of its plans.

According to Faust’s statement, the Science Complex’s foundation will be completed and brought to ground level at a slower pace while planners conduct detailed cost analyses to determine whether to keep current plans, reconfigure the building to cut costs, or halt construction completely.

Faust said the rest of Harvard’s Allston planning—which has been slated to occur over a 50-year time span—will also slow. She added that Harvard will “develop options for interim improvements to [its] existing properties” as well as deliver on its previously agreed-upon community benefits.

Harvard programs promised space in the complex, such as the Harvard Stem Cell Institute and the much-heralded Department of Stem Cell and Regenerative Biology, would instead move into renovated spaces in Cambridge, according to the statement.

—Staff writer Peter F. Zhu can be reached at pfzhu@fas.harard.edu