Chelsea have made a formal approach to Leicester City for midfielder N'Golo Kante and are set to trigger the £20m ($26m) release clause in his contract.
The Daily Telegraph reports that the Blues have stepped up their pursuit of the France international after Chinese club Shanghai SIPG tabled a £35m offer to Leicester for the defensive midfielder.
Kante is understood to prefer a move to Stamford Bridge, although Chelsea may have to pay more than £20m for his signature.
This is because the release clause written into Kante's contract, which runs until 2019, still allows Leicester to sell him to the highest bidder.
The 25-year-old has reportedly rejected a new £100,000-per-week contract at the King Power Stadium and is free to negotiate with the other clubs now that the European Championships are over.
New boss Antonio Conte begins work at Chelsea this week before travelling with the club to Austria for a pre-season tour at the weekend.
He has already had a bid for Radja Nainggolan rejected by Roma this summer, as he strives to add more energy to the Blues midfield.
Aside from Kante, the Italian coach is also keen to sign defender Kalid Koulibaly from Napoli and striker Alvaro Morata from Real Madrid.
Belgian striker Michy Batshuayi, signed for £33m from Marseille, has been the only fresh arrival at Stamford Bridge this summer.
Kante enjoyed a hugely impressive 2015/16 club season with title-winning Leicester, playing 33 Premier League games and scoring one goal. He also made four appearances for France at Euro 2016.
The defensive midfielder was signed by Leicester for £5.6m from Caen last summer.
Manchester United, Arsenal and Juventus have all been linked with the player, but Chelsea have emerged as the favourites for his signature.
Blues players who were not involved in the knockout stages of Euro 2016 or Copa America reported back to the club's Cobham base for pre-season training on 11 July.