WINNIPEG (CP) - Canadian National Railway applied Thursday for a court order to prevent Manitoba First Nations protesters from blocking its rail lines to protest the Canadian government's handling of aboriginal land claims negotiations.

Last week, Chief Terry Nelson of the Roseau River Anishinabe First Nation said CN and Canadian Pacific Railway tracks would be affected by the blockades, which he said would start at 4 p.m. on June 29 and last for 24 hours.

The protest has the support of the Assembly of Manitoba Chiefs, while First Nations from other provinces might also get involved, Nelson said.

CN said Thursday it had filed an action in the Manitoba Court of Queen's Bench seeking an injunction to prevent a blockade of its rail lines.

"CN has no authority to resolve First Nations' land claims disputes with the federal government, and said rail blockades would be unsafe and unfairly harm CN, its customers and their employees, and the national economy," CN said in a release.

The Montreal-based company, Canada's biggest railway, said it had also asked First Nations to reconsider their blockade plan and urged them to pursue alternative dispute-resolution mechanisms with the government.