Former Hammers defender Bilic is a leading contender to take over at Upton Park following Alan Curbishley's resignation earlier this week.

Bilic has already insisted he is committed to taking Croatia to the 2010 World Cup after reports suggested the Hammers want to appoint him after next week's qualifier with England.

And Markovic has warned the Premier League club that an approach would be futile, saying Bilic's departure would create a "big political problem".

"It will be mission impossible," said Markovic in the Daily Express.

"Bilic can't go because there will be a big political problem with Croatia. This is the usual speculation.

"Bilic can't go and, even if he loses against England, he is not going to leave as we are very happy with him.

"They might have money, but so do we and the Croatian FA has enough money to buy West Ham."

Bilic told Croatian sports daily Sportske Novosti: "I always said West Ham will be my choice when I return to England.

"However, my contract with the Croatian FA expires in 2010 and I am intending to lead Croatia in this period."

One former West Ham player who has thrown his hat into the ring is controversial Italian striker Paolo di Canio, according to his agent Phil Spencer.

Spencer said: "We have made moves to talk to West Ham and advised them that he [Di Canio] wants to be considered. He wouldn't be putting himself up for the job if he didn't think he was capable of doing it.

"He just wants the opportunity to sit in front of the decision-makers at West Ham to tell them what he would do and how he would take them forward."

Meanwhile, Hammers midfielder Mark Noble believes the team were heading in the right direction under Curbishley, who quit due to the club's transfer dealings.

Noble said: "Without the injuries last year and if a couple of results had gone our way we could have changed things.

"We finished 10th, but we always said that last season was going to be a stepping stone.

"Alan is a proud man, but I don't know what is going on. He resigned and it was his decision."