Turkey has again extended the deadline for bidding companies to send revised offers for its anti-ballistic missile air defense system.

The new deadline for rival bidding companies to submit their proposals is April 30, allowing U.S. company Raytheon Co and Lockheed Martin Corp and Italian-French team Eurosam SAMP/T to revise their offers and try to head off a Chinese company, with which Turkey is still in talks.

Turkey announced its decision to negotiate with China’s Precision Machinery Import and Export Corp. (CPMIEC) to co-produce anti-ballistic missile system last September. It then extended the deadline to Jan. 31, after firm statements from NATO and U.S. officials that the Chinese MD-2000’s would not be interoperable with the NATO defense architecture. Turkish leaders said the deal had yet to be finalized, and that Ankara remained open to new offers from the other two bidders.