Four Sevilla players could face action from their club and the authorities after photos shared on social media appeared to show them breaking quarantine rules.
The city of Seville remains in "Phase One" of Spain's gradual relaxation of lockdown measures, in which a maximum of 10 people are permitted at social gatherings.
Sevilla are yet to comment on the allegations, but the players individually acknowleged the error on their social media accounts on Sunday.
"I want to apologise for what happened yesterday," Banega said on Instagram. "It was a family get together with teammates but unknowingly, we were wrong. I want to apologise to our club, fans and society in general. It won't happen again."
💥 Ocampos, Mudo Vázquez, De Jong y Banega se saltan las normas de cuarentena— MARCA (@marca) May 24, 2020
⚠️ La mujer de Banega ha compartido imágenes de una reunión ilegal en la fase 1... borradas poco despuéshttps://t.co/obLeV0iR8t Te lo cuenta @sergiofmarca
La Liga president Javier Tebas addressed the matter on Sunday but did not say if the players would face any sanctions.
"I'm not going to say publicly if La Liga is taking disciplinary action. The players have apologised. In football we're an example to society," Tebas said. "We have to be really careful. We're putting 180,000 jobs at risk and 1.37% of Spain's GDP. Someone without symptoms could have been at that gathering."
Players in Spain are required to follow strict quarantine rules as part of a protocol for a return to training drawn up by La Liga and approved by the country's Ministry of Health.
"Players need to be responsible. I've said that in training and at games it's practically impossible for infection to happen," Tebas added. "It's these other places, these meetings that worry me."
Initially, the league had wanted players to be isolated in training camps to coincide with the group training phase, but that requirement was dropped after talks between La Liga and the players' union AFE.
Clubs are awaiting the go-ahead to move to full training sessions involving their entire squads in anticipation of a return to competition.
On Saturday, Spain's prime minister Pedro Sanchez gave the green light for La Liga to resume from June 8, with the first game expected to be the derby between Sevilla and Real Betis on Friday, June 12.
Spain has seen over 235,000 confirmed coronavirus cases and more than 28,000 deaths since the coronavirus pandemic began.