Fraport AG (FRA.XE) Chief Executive Stefan Schulte Thursday confirmed that the German airport operator has submitted a joint bid with Deutsche Bank AG's (DB) infrastructure investment unit RREEF for a portfolio of airports put up for sale by construction company Hochtief AG (HOT.XE).

"We have submitted a joint bid with RREEF," Schulte told reporters on the sidelines of a logistics and mobility industry conference in Frankfurt.

His comments come after Hochtief Chief Executive Frank Stieler Wednesday said the company had received several offers for its airport portfolio, but didn't mention how many bidders are in the process. The deal is expected to close this year, according to Stieler.

The assets include minority stakes in airports in Athens, Budapest, Dusseldorf, Hamburg, Sydney and Tirana, Albania.

People familiar with the bidding process have said four suitors are still in the running, having placed bids of up to EUR1.3 billion.

Apart from Fraport and RREEF, the bidders include French construction company Vinci SA (DG.FR) and the parent of Hainan Airlines Co. (600221.SH), China's No. 4 airline by revenue. A fourth bidder is a consortium comprising Allianz SE's (ALV.XE) investment arm Allianz Capital Partners and infrastructure fund Global Infrastructure Partners.

Fraport's Schulte said Thursday that his company is solely interested in the international airport assets held by Hochtief's Concessions, adding that its partner RREEF has its eyes on the German assets.

Schulte declined to elaborate further on the matter, saying only that the two joint bidders would work out how to split up the international and German assets owned by Hochtief Concessions after a successful bid.

-By Jan Hromadko, Dow Jones Newswires; +49 69 29 725 503; jan.hromadko@dowjones.com