GALLUP, N.M. (AP) — The owners of a coal-fired power plant in northern Arizona have rejected the Navajo Nation's request for a 30-day extension of a July 1 deadline for the tribe to decide whether to extend the owners' lease for the site.

The Navajo Generating Station owners rejected the extension request Wednesday, The Gallup Independent reported (http://bit.ly/2o70OE6).

The owners have said the plant must shut down by the end of 2017 if a longer lease is not approved by July 1 to provide time to remove the plant by the end of its current lease at the end of 2019.

A Navajo Nation Council committee requested the extension in hopes of gaining more time to review the 800-page lease legislation.

"With respect to the July date, we are at a wall," said Mike Hummel, Salt River Project deputy general manager, told the committee.

The plant and a coal mine that supplies it employ about 750 people, almost all being Native Americans.

Utilities with shares in the plant want to bow out because they can get the power cheaper from natural gas sources.

Council Speaker LoRenzo Bates, who is sponsoring the lease legislation, has said the plant's owners set the July 1 deadline, while Hummel said it was negotiated by the tribe and the plant's owners.

The tribe worked for four months to negotiate the proposed agreement, and council delegates were part of the tribe's negotiating team, Hummel said.

The owners began raising concerns in February that July 1 was five months away, he said. "July didn't sneak up on anyone," Hummel said.

Hummel said the tribe and the owners also need to separate the decision to extend the current lease from the possibility that the tribe may want to operate the plant after 2019.

Bates said he would schedule a special committee meeting for a vote on the lease legislation and then forward it to the full council for final action.