Nashville Predators forward Alex Radulov was one of six players whose new contracts were suspended by hockey's international governing body on Friday until the legality of the deals could be investigated.

Radulov, under contract for another season with the Predators, signed a contract with a Russian team in the new Continental Hockey League (KHL). That deal seemingly would be in breach of a pact agreed to July 10 between the KHL, the NHL, the NHL Players' Association, and international hockey leagues in which contracts worldwide would be honored and respected.

But the KHL contends the deal between Radulov and his KHL team was reached two days before the leagues agreed to obey existing contracts.

The International Ice Hockey Federation told the NHL, the NHLPA and the KHL that the international transfers of Radulov and five others are officially under investigation.

Nikita Filatov, Viktor Tikhonov, Jason Krog, Tomas Mojzis and Fedor Fedorov are also having their deals reviewed. All parties have until July 31 to submit documentation to the IIHF.

"We hope that this can be resolved amicably and in a timely manner," IIHF president Rene Fasel said Friday. "It is unfortunate that we are already facing such difficulties after the progress that was made last week.

"I am hoping that all sides can come to a solution."

Problems arose due to the lack of a transfer agreement between the NHL and KHL. A signing moratorium was established after representatives from the NHL, NHLPA, and IIHF met last week in Zurich, Switzerland, but the deal has yet to be signed.

The six players won't be eligible to participate in international transfers and competitions while the investigation is ongoing.

Filatov was chosen by the Columbus Blue Jackets with the No. 6 pick in the first round of the June draft and recently agreed to terms on an entry level NHL contract. Tikhonov, chosen No. 28 by Phoenix, came to terms with the Coyotes. Both players' Russian teams say they already had deals in place.

Krog, an NHL veteran, signed with Vancouver after he reportedly came to terms with a team in Russia. Mojzis, who played last season in Russia, has a new deal with the Minnesota Wild.

At the Zurich meeting, the groups agreed not to sign players under contractual obligations. A committee was formed to draft a document that would specify the terms of such an agreement, including the handling of possible disagreements regarding the validity of contracts.

The KHL said it would accept the investigation, provided it was conducted within the framework of relevant legislation in the U.S., Russia and Canada, and in accordance with the labor law regulations of the NHL and KHL.

However, the KHL strongly opposed the decision to suspend these players.

"We do not accept the idea of suspending the contracts because this has not been agreed on by KHL and NHL," KHL president Alexander Medvedev said in a statement. "The mentioned players should not be made 'scapegoats' due to the fact that the memorandum of agreement has not been signed between the KHL and the NHL.