Spain international Sergio Busquets conceded it will be difficult to sort out the situation involving team-mate Gerard Pique as the Barcelona defender continues to be targeted by national team supporters.
Pique's outspoken support of Catalonia's independence referendum saw him booed by a number of fans at Spain's training session on Monday.
Political tensions in the country continue to spill into sport after LaLiga leaders Barcelona defeated Las Palmas 3-0 behind closed doors at Camp Nou on Sunday amid unrest in the region, which resulted in clashes between the public and police after the central government deemed Sunday's vote illegal.
"I would say this is my most difficult spell in the national team due to everything that is happening and I think it will be difficult to sort out the Pique situation," Busquets told Cadena Ser.
Busquets added: "There has been no meeting in particular to deal with the Pique situation.
"I do not know if [captain Sergio] Ramos and Pique have spoken but it is not a usual situation.
"As for Pique he seems the same as ever."
Spain are preparing for a pair of World Cup qualifiers against Albania on Friday and Israel four days later.