(AP) — A White House official says President Barack Obama is telling the State Department it shouldn’t approve the Keystone XL pipeline unless it’s sure the project won’t increase greenhouse gas emissions.

Obama will make the announcement Tuesday in a speech on his climate change plan at Georgetown University. That’s according to a senior White House official, who wasn’t authorized to discuss the announcement by name ahead of Obama’s speech and spoke on condition of anonymity.

Environmental activists have been pleading with Obama not to approve the pipeline, which would carry oil extracted from tar sands in western Canada to refineries along the Texas Gulf Coast. The White House has insisted the State Department is making the decision about whether the pipeline is in the national interest.