Brighton have rejected a second bid from Arsenal for Ecuador midfielder Moises Caicedo and told the Premier League leaders he is not for sale.

The latest bid is thought to be in the region of £70m. Arsenal and Chelsea both had offers for the 21-year-old turned down last week.

Caicedo informed Brighton in an open letter that he wanted a move, with the club responding by telling him to take time off until after Tuesday’s transfer deadline.

He missed Sunday’s 2-1 FA Cup win over Liverpool with manager Roberto de Zerbi saying he wants Caicedo to finish the season with the club.

Brighton are sixth in the Premier League, five points behind fifth-placed Tottenham, but with two games in hand on Antonio Conte’s side.

“[Brighton chairman] Tony Bloom knows very well my opinion. We lost [Leandro] Trossard and if we also lose Caicedo it’s a problem for us if we want to fight for Europe,” De Zerbi said on Sunday. “If we don’t lose Caicedo we are ready to fight.”

The Seagulls, who sold Trossard to league leaders Arsenal for £21m plus add-ons earlier this month, have already turned down a £60m bid from the Gunners for Caicedo, and also reportedly rejected an earlier £55m offer by Chelsea. Before Sunday’s game, the Brighton boss said Caicedo had made a “mistake” in asking to leave the club.

“For everyone there are many solutions. We will see the best solution for him and for us,” the Italian said.

Caicedo has made 26 appearances for Brighton in the Premier League, scoring twice, and is under contract until 2025.