Mesic accused General Ante Gotovina of being responsible, alongside the late General Janko Bobetko, for the death of 185 soldiers in the operation which he described as "unprepared. It didn't move us forward one inch and was carried out for election purposes".
"(It's not true that) 185 people died in that operation. It's disgraceful to claim that the front line had not moved an inch and it's scandalous to bring into question the sacrifice of the soldiers who were killed," branch president and party vice president Stanko Zilic told a press conference in the central coastal city of Zadar.
He said he respected the institution of the president of state, but added it would be "nice if Mesic admitted he was old and simply resigned".
Zrilic said Mesic had no moral right to question General Gotovina's courage, patriotism and knowledge. Gotovina is wanted by the Hague war crimes tribunal.
The Zadar County branch of the Association of Homeland War Volunteers issued a statement describing Mesic's statement as disgraceful and urged him to tender an irrevocable resignation.
The chairman of the Disabled Homeland War Veterans Association (HVIDRA) Main Committee, Josip Perisa, told the press in Sibenik that Mesic's statement about Operation Maslenica insulted generals Bobetko and Gotovina as well as all who had taken part in it. Perisa said the president should file an action if he had evidence to corroborate his claims.