Javi Martinez has not been told why he was left out of Spain's latest squad by head coach Julen Lopetegui.
Bayern Munich defender Martinez was among the notable absentees from the squad for international friendlies against Germany and Argentina on March 23 and 27 respectively, along with Chelsea duo Alvaro Morata and Cesc Fabregas.
The World Cup is three months away but Martinez - part of the group that won the 2010 World Cup and 2012 European Championship - confirmed he has not been contacted by Lopetegui regarding his surprise omission.
"He never called me or said nothing about it," Martinez told ESPN.
"I know it's very difficult to get in the national team. There are such good players there. It's very difficult. Of course, I worked very hard to try to go there. I want to keep working hard.
"It's true that here, a lot of people asked me - are surprised about why I'm not going on, but I think I have to work. I don't give up and I keep working to try to reach the goal.
"I will keep working and will try 100 per cent. Of course, it's one of my biggest goals to be in the World Cup and I will fight very hard, but I told you, it's very difficult to get in, but if I'm not going, if nothing happens, I have to keep working and it's not the end of my career."
Martinez has not featured for Spain since the 2014 World Cup, but the 29-year-old was called up for friendlies last year.