Chelsea have identified Leicester defender Ben Chilwell and Ajax midfielder Hakim Ziyech as priority summer transfer targets, sources have told ESPN, but the club are facing defeat in their attempts to sign Napoli forward Dries Mertens.

Manager Frank Lampard has been given the green light to rebuild his squad in the summer, with substantial funds available following the lifting of the club's two-window transfer ban.

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And Chilwell, 23, and Morocco international Ziyech are top of Lampard's hit-list as he attempts to replace title-winning left-back Marcos Alonso and add more creativity to his team's attacking options.

Sources have told ESPN that Lampard had been keen to sign Belgium striker Mertens this month, but the 32-year-old has shown little appetite to leave Napoli, who have placed a prohibitive £40 million price tag on the former PSV Eindhoven forward.

While Chelsea could renew their interest in Mertens at the end of the season, efforts will initially focus on overcoming interest from Manchester City and Manchester United in England full-back Chilwell.

The £80m-rated full-back is expected to make Gareth Southgate's squad for Euro 2020 and Lampard believes he could offer Chelsea the stability and quality at left-back that they have lacked since Ashley Cole's departure in 2014.

United are also eyeing a move for Ziyech, but Chelsea have moved ahead of the Old Trafford outfit in the race to sign the Netherlands-born Moroccan.