The decision led to an outburst from new manager Stuart Pearce.
Al Hasawi said in a statement: "I would love nothing more than to hold on to our best young players. I gave both Karl Darlow and Jamaal Lascelles lengthy new contracts in August 2013 and March 2014 respectively, as well as investing in the futures of Jamie Paterson, Ben Osborn and Dimitar Evtimov.
"I have demonstrated my keenness for the club to produce more players of Karl and Jamaal's quality more than ever this summer, investing heavily in the facilities and supporting Stuart in his desire to integrate our youth set-up with the first team.
"The manager and I openly discussed the proposed sale of Karl and Jamaal and he was aware of the negotiations throughout. The business side of football is changing and the requirement to increase revenue means, unfortunately, difficult decisions have to be made. As Stuart mentioned in his media interview, I have always backed him financially and that will continue. I respect him greatly and I strongly believe together we can achieve our aims and bring success back to this great club.
"Should the pair's proposed move to Newcastle be completed as expected, the transfer fees will significantly help us meet the stringent financial fair play (FFP) criteria, all the while allowing us to retain two high-quality players for the 2014-15 season, paying nothing towards their wages.
"Sadly for me, there is no room for sentimentality in the running of a football club and it is up to me to start making some tough decisions to preserve the long-term sustainability of Nottingham Forest."
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