"I will be the president who will lead Croatia into the EU," Mesic said in an exclusive interview with the German news agency Deutsche Presse-Agentur (DPA), released on Saturday evening.
DPA said that Mesic would seek his second five-year term in office at presidential elections scheduled for January 2.
"The European Union told us (at the Brussels summit) we need to fully cooperate with the ICTY. Completely. They did not say (specifically) that we are obliged to extradite Gotovina, because if Gotovina is not in Croatia, we cannot extradite him," Mesic said.
"What we need to do is check every possible trace which might lead to Gotovina. We also must check traces going outside Croatia, and in that case institutions of other countries must cooperate with us," he added.
The ICTY indicted General Ante Gotovina in 2001 for crimes against humanity and violations of the laws and customs of war committed during the Croatian army operation Storm in 1995.
EU leaders told Zagreb to fully cooperate with the Hague tribunal, which means that Croatia needs to do its best to arrest and extradite the fugitive general, the agency said.
Mesic went on to say that "full cooperation means checking those traces," adding that "there is no single reason why we (Croatia) would protect Gotovina since we extradite all other indictees."
The human rights organisation Amnesty International (AI) harshly criticised Zagreb on Monday for failing to bring to justice persons responsible for war crimes committed during the Homeland War in the 1990s. AI said that there was ethnic bias in Croatian courts, suggesting that ethnic Serbs have a greater chance of being convicted for war crimes than ethnic Croats.
"If anybody has been criticising the Croatian judiciary, that would be me. There were cases that were not in line with European standards. I am for reform of the judiciary, and also, that everybody (regardless of their ethnicity) is equal before the law," Mesic said.
According to the Croatian president, the problem is in the lower courts that were handing down "unacceptable verdicts" that made it "obvious that the length of jail terms depended on the ethnicity of the indictees".
Mesic also believes that successful membership talks between Croatia and the EU will have positive implications for the rest of the war-torn Balkan region by showing that a country once involved in wars can democratise itself, DPA said.
"We will be an example to others that it pays off to fight for European standards," Mesic said.
Mesic also said he had done a lot to democratise the country since he became president in 2000. "Nobody was coming to Croatia, our representatives were not travelling anywhere," he said, speaking of the time when he took office. "But today, we are a desirable partner that fights for adoption of European standards."
Mesic said that opening Croatia was one of his biggest successes, adding that "nationalism no longer poses a threat for us."
DPA cited results of the latest opinion polls, according to which Mesic can count on the support of between 50 per cent and 56 per cent of the voters, while his main rival, Deputy Prime Minister Jadranka Kosor can expect to receive between 17 per cent and 24 per cent.