Chinese online video companies Tudou Holdings and Youku.com said they will sue each other for alleged copyright infringements of their videos.

Tudou said late on Monday that it would take legal action against Youku, China's top online video site, for allegedly reposting episodes of a popular variety program on Youku's platform.

Cti TV, the legal copyright holder of Kangxi is Coming, signed an exclusive agreement with Tudou in November to distribute the episodes of the program on its platform, Tudou said in an emailed statement.

Tudou and Cti TV allege that the episodes were then copied by Youku and uploaded onto Youku's platform.

Youku subsequently countered on Friday that it would take legal action against Tudou, accusing Tudou of allegedly pirating more than 60 television serials from Youku.

Youku said in a statement that legal mediation between the two sides had failed.

The battle for content in China's online video space has heated up this year with costs for programs rising significantly as online video players scramble for eyeballs to lure advertisers.

Advertising revenue in the domestic online video market, which was virtually non-existent five years ago, is now estimated to be worth 1 billion yuan ($156.90 million). This is expected to grow at a double-digit rate.

Many online video players have also signed deals with Hollywood studios to boost viewership.

Shares of Tudou closed 2.51 percent lower on the Nasdaq on Thursday, while Youku fell 3.75 percent on the New York Stock Exchange.

($1 = 6.3735 Chinese yuan)

(Reporting by Melanie Lee; Editing by Jacqueline Wong and Matt Driskill)