Major blow to Keystone XL pipeline as judge revokes key permit

Campaigners welcomed Wednesday's ruling as a victory for tribal rights and environmental protection

The controversial Keystone XL tar sands pipeline has been dealt a major setback, after a judge revoked a key permit issued by the US army corps of engineers without properly assessing the impact on endangered species.

In a legal challenge brought by a coalition of environmental groups, a federal judge in Montana ordered the army corps to suspend all filling and dredging activities until it conducts formal consultations compliant with the Endangered Species Act.