Mesic was speaking to reporters who were covering a ministerial meeting of the US-Adriatic Charter attended by foreign and defence ministers from Croatia, Albania, and Macedonia, as members of the Charter, and representatives of the US government and the foreign and defence ministers of Estonia, Latvia and Lithuania.
Mesic addressed participants in the Brijuni meeting during the first of the four sessions focusing on the topic "Preparations for the next NATO enlargement round: Riga summit and the prospects thereafter".
"I believe that the position that Croatia could definitely expect membership (of NATO) could crystallise in Riga, but when exactly that will happen remains to be seen," Mesic told reporters.
"I hope that by the next summit after Riga Croatia could receive an invitation," he added.
Mesic said the Brijuni meeting was yet another sign of support for Croatia's admission to Euro-Atlantic associations, notably NATO.
The meeting also marks the beginning of more significant cooperation with the Baltic countries which have more experience with integration with NATO, Mesic said.
"I think that the support of the United States is so transparent that it does not require any special comment," he added.
Asked if the signing of a bilateral agreement with the USA on the non-extradition of US citizens to the International Criminal Court would be discussed during the upcoming visit of US Vice President Dick Cheney to Croatia, Mesic said that the issue would not be discussed.
The president is scheduled to take part in the second session without addressing it. The session will be addressed by European Integration and Foreign Affairs Minister Kolinda Grabar Kitarovic and Defence Minister Berislav Roncevic.