West Ham have made an improved offer worth £30m for Manchester United defender Harry Maguire.
The Hammers had a £20m bid for the England international rejected last month.
West Ham also submitted a separate £30m bid for Manchester United midfielder Scott McTominay, which the Old Trafford club have rejected.
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United are happy to keep McTominay, but value him closer to £45m and acknowledge he could be the biggest sale they could make this summer.
His international form, age, professionalism and physical conditioning enables the club to hold out for their price point.
Manchester United are not pushing the players out, but will consider offers that reflect "fair market value".
Meanwhile, West Ham have an agreement in principle with Ajax over the signing of midfielder Edson Alvarez with the club paying an initial £32m plus £2m in performance related add-ons.
Personal terms have been agreed and Alvarez is expected to fly to the UK on Tuesday for a medical.
Explained: Is a power struggle at West Ham affecting transfers?
Sky Sports News chief reporter Kaveh Solhekol:
"You have to go back to last summer and remember that the people who own West Ham were unhappy with the transfer business that was done. They spent more than £200m and were one of the biggest spenders in world football.
"They signed eight players and some of them worked out but quite a few of them didn't. They wanted a change and brought in a new technical director in Tim Steidten from Germany with a brilliant reputation at Bayer Leverkusen.
"Everyone I speak to says he's got an incredible football brain and knows everyone in the game. He knows about up-and-coming players. West Ham wanted to shift their focus away from the English market to the European and worldwide market.
"But when you look at the players they've been making bids for, they've been making bids for tried and tested Premier League players - Joao Palhinha, Conor Gallagher, Scott McTominay and Denis Zakaria - who was at Chelsea last season.
"I don't think they've been making bids for the players that Steidten has been recommending. So there's a little bit of friction and a power struggle behind the scenes. Ultimately, David Moyes is the manager and he will have the final say."
Scamacca joins Atalanta
West Ham striker Gianluca Scamacca has left the club for Serie A side Atalanta just a year after his £30.5m arrival.
The 24-year-old Italian, who joined the Hammers from Sassuolo last summer, has completed a permanent move for an undisclosed fee believed to be around £27.5m.
A statement on West Ham's official website said: "West Ham United can confirm that Gianluca Scamacca has departed the club and joined Atalanta BC.
"The 24-year-old has moved to the Italian Serie A side on a permanent transfer for an undisclosed fee.
"The centre-forward spent a single season at London Stadium and scored eight goals in 27 appearances, including five in the Hammers' run to lifting the UEFA Europa Conference League.
"West Ham United would like to thank Gianluca for his efforts and wish him well for his future career."
Italy international Scamacca made his Premier League debut as a substitute in a 2-0 home defeat by Manchester City on August 7 last year and scored his first goal in a 3-1 Europa Conference League victory over Viborg 11 days later.
However, he started only 16 times for the club during his season in England.
A statement on Atalanta's official website said: "Atalanta B.C. would like to extend a warm welcome to Gianluca and wish him the best of luck in his future personal and team endeavours as a Nerazzurro."
Vlasic to Torino agreed
Torino have agreed an £11m deal with West Ham over the permanent signing of forward Nikola Vlasic.
The 25-year-old Croatia international will undergo a medical at the Serie A club on Tuesday.
Vlasic joined West Ham from CSKA Moscow for around £27m in the summer of 2021 and spent last season on loan at Torino.
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