Turkish construction firm Cengiz is in talks about buying up to 49 percent of the $20 billion Akkuyu nuclear power plant being built by Russia's Rosatom, a source familiar with the matter said Wednesday.The Russian-owned project, Turkey's first nuclear power plant, has been complicated by the deterioration in ties between the two countries after Turkey shot down a Russian warplane over the Turkey-Syria border in November.In December, Turkish energy officials said state-owned Rosatom had stopped construction work on the project. President Vladimir Putin subsequently said the decision on the future of the plant would be purely commercial. "Talks have been continuing for some time with Cengiz Construction on the sale of up to 49 percent of Akkuyu," the source told Reuters. Rosatom declined to comment on the issue. Cengiz last year won a tender to build some of the Akkuyu plant's structures. Established in 1987, Cengiz İnşaat Sanayi ve Ticaret A.Ş., which is a subsidiary of Cengiz Holding, is one of the most renowned Turkish construction companies.The total value of the company's ongoing projects within the country currently amount to approximately $7.85 billion. The sale of a 49 percent stake is a provision of the inter-government agreement to build the plant signed by the two countries in 2010. Talks on the sale have been held with other investors previously and could be held again, the source said. He said there was no timescale for the sale adding that there was no political dimension to the sale. "The sale of the shares has nothing to do with the political process between Turkey and Russia following the downing of the plane," he said. The Akkuyu plant is not scheduled to come on online before 2022 and has faced delays due to regulatory hurdles and Moscow's financial woes. In 2013, the Turkish government picked a Japanese-French consortium to build a second nuclear plant at an estimated cost of $22 billion.