West Ham have signed attacking midfielder Nikola Vlasic from CSKA Moscow and Alex Kral from Spartak Moscow.
Vlasic, 23, has signed a five-year deal with the London club for a fee reported to be in the region of £25 million, while Kral arrives on a season-long loan with an option to buy.
Vlasic was named Russian Premier League Footballer of the Year in 2020, and is a regular for the Croatia national team, making four appearances at Euro 2020.
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He adds depth to David Moyes' attacking options at the London Stadium as West Ham prepare to begin their Europa League campaign.
Moyes' side are currently second in the Premier League after an unbeaten start to the season.
"I am delighted to welcome Nikola to West Ham United," said Moyes.
"I have been watching Nikola improve over recent seasons - he has got a good goals and assists record during that time and I feel there is more to come from him.
"I was really impressed with how determined Nikola was to become a West Ham play.
"That hunger and ambition fits with what we are trying to build here."
Vlasic previously spent two years at Everton after emerging as one of Europe's most promising prospects as a teenager at Hadjuk Split. The Croatian departed for Moscow, initially on loan, in 2018.
West Ham had been keen to add to their squad after Jesse Lingard returned to Manchester United following a successful loan spell last season.
Lingard had been linked with a return to the club but that would now appear unlikely.
Said Benrahma and Pablo Fornals have each started the season well in creative roles behind striker Michail Antonio.
West Ham have been drawn alongside Dinamo Zagreb, Rapid Wien and Genk in Group H of the Europa League.
They open their campaign in Zagreb on 16 September.
The Hammers have also signed Alphone Areola and Kurt Zouma this summer, while Craig Dawson's loan from Watford. was converted to a permanent deal.

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The club also confirmed that promising striker Mipo Odubeko had extended his contract on deadline day. Odubeko has joined Huddersfield Town on loan until the end of the 2021/22 season.
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