The White House is threatening to veto a transportation bill if it also mandates construction of the Canada to Texas Keystone XL oil pipeline.

President Obama already blocked the $7 billion TransCanada pipeline, which would have transported crude oil to Texas refineries, last March.

House Republicans included the pipeline in legislation to extend funding for highways and bridges by 90 days.

The White House said that would bypass "longstanding and proven process" on how to determine if cross-border pipelines serve the national interest.

The pipeline may be dropped from the bill for now, but it could be restored later in a conference committee with the Senate.