White House: Keystone pipeline review needs time

"There is a reason why this process has within it the duration required to properly review all the different aspects of a project like this, and to weigh all the different criteria," White House spokesman Jay Carney said.

Carney told a news briefing there has not been an alternate route mapped out for the Canada-to-Texas pipeline and that the state of Nebraska needs six to nine months to do its own environmental assessment. He did not say whether the late-February decision deadline imposed by payroll tax legislation would force the Obama administration to reject the permit.

(Reporting By Laura MacInnis and Aruna Viswanatha; Editing by Sandra Maler)