Sevilla president Pepe Castro has warned Grzegorz Krychowiak's suitors that they would have to pay the full €30m (£21.7m) release clause of the coveted midfielder to secure his services, with both Arsenal and Southampton believed to be monitoring his situation.

The 25-year-old midfielder moved to the Europa League winners last summer after they paid €4m to Stade de Reims.

But the Polish international's value has drastically increased after he became a crucial asset for Unai Emery during Sevilla's successful campaign, providing balance to the midfield and even scoring a goal in the Europa League final 3-2 victory over Dnipro.

The Times recently reported that Arsene Wenger has identified him as a cheaper alternative to Morgan Schneiderlin due to Southampton's high demands for the France international.

Meanwhile, reports in Spain this week claimed Ronald Koeman's side have also made a €12m bid to secure the services of the Polish midfielder, as the Dutch boss prepares for life without Schneiderlin.

Castro claimed that after selling Aleix Vidal to Barcelona for £16m, Sevilla do not need to cash-in with more players – but admitted he can not guarantee Krychowiak will stay if any suitor pays his buy-out clause.

"Our idea is [someone pays his] release clause or nothing" Castro said, while adding: "We want to maintain our supremacy. We have made a sale that gives us peace and we do not need to sell any more players. Our idea is to keep all these players who have had a magnificent season.

"Vidal's selling has been, as you all known, for a fee above the market value. We are not going to sell easy but we are aware that in football you can never say never but you can say pay the release clause or nothing."