Newcastle will do everything in their power to keep Alexander Isak on Tyneside and have let Chelsea and Arsenal know that it would take an astronomical offer to alter that stance.

Chelsea have made an initial inquiry for the Sweden striker but, given that club’s problems with ­meeting profitability and sus­tainability rules (PSR), there is considerable doubt at St James’ Park that they would be capable of paying a sum possibly well in excess of £100m for the 24-year-old.

Despite making it clear that Chelsea would need to break the record £115m they invested in prising ­Moisés Caicedo away from Brighton last August, Newcastle have no real desire to sell a striker around whom their manager, Eddie Howe, ­envisages building his team.

Related: Big week in a big summer for Newcastle and Eddie Howe

Arsenal harbour a longstanding interest in Isak, but they have yet to make formal contact after apparently being deterred by Isak’s price. Newcastle hope to extend the player’s contract this summer and remain confident the former Real Sociedad forward is happy and settled in the north-east.

His deal expires in 2028 and a player who has scored 35 goals in 67 appearances for Newcastle since arriving from Spain for about £65m two years ago told Sweden’s Fotbollskanalen he was not seeking a new club. “I’ve just had the best season of my career,” said Isak, who finished last season as Newcastle’s top scorer with 25 goals.

“I’m really happy at Newcastle. I love everything about it; the club, the fans and the city. My future is not something I will speculate on. I have no thoughts on leaving. There has been no talk about it at the club and I have received no information that the club would have to sell me.”

For their part, Newcastle remain optimistic they can remain on the right side of PSR rules without selling Isak or their ­Brazil midfielder Bruno Guimarães and continue to seek, among other players, a right-sided centre‑half. Contact has been made with Milan regarding Fikayo Tomori but the Serie A club are asking for a fee of more than £40m and it is unclear whether a compromise can be reached.

Sunderland, meanwhile, have rejected offers from several clubs, including Crystal Palace, for Jobe Bellingham and remain determined to keep hold of the England Under-19 midfielder this summer. Bellingham, who is valued at more than £20m by Sunderland and has four years left on his contract, has emerged as a target for Palace’s sporting director, Dougie Freedman, after some impressive performances in the Championship this past season.

Brentford, Tottenham and clubs from Spain and Germany are also believed to have registered an interest in Bellingham – the younger brother of Jude – who scored seven goals in 45 league appearances.