ANKARA (Reuters) - The door remains open for international engine-makers to get involved in Turkey’s TF-X national fighter jet project, Turkish Defence Industry Director Ismail Demir said on Thursday.

Turkey has in recent years been working to develop its own defense vehicles, including tanks and combat helicopters, in an attempt to boost its defense capabilities amid militant threats and conflict along its southern borders.

Last year Turkey’s Kale Group said it would set up a joint venture company with UK-based engineering firm Rolls-Royce to develop aircraft engines including those of the TF-X, Turkey’s first domestically made jet. Britain and Turkey signed a deal worth more than 100 million pounds to develop TF-X.

Speaking at a signing ceremony with defense company TR Motors for the jets' production, Demir said talks with Rolls Royce RR.L were underway, but that Turkey had "red lines" regarding the project which it would not compromise.

Demir said there should be no restrictions on exports, that all the technology will belong to Turkey, and that Turkey will own all its rights.

“An engine that belongs fully to us is our red line. Since we know it will be a long process, we will work with those who want to produce an intermediary engine,” Demir said.

Asked whether Rolls Royce had agreed to comply with the demands, Demir said Turkey would be willing to forego the red lines for a prototype engine, but not for the final product, and added that other international offers would also be evaluated.

Demir also said Turkey was at a stage where it could start mass production of its national Altay tanks, adding that they were looking at a period of 18 months after the signatures.

The Altay tank project, led by the Turkish commercial and military vehicle producer Otokar, is worth an estimated 7 billion euros ($8.30 billion).