Vucic said Serbia was "investing its money in the economy, while it will invest nothing, or not much, in weapons if Croatia decides not to arm itself with missiles."
Vucic said that this policy will continue "for as long as he serves as prime minister."
Asked how much money Serbia would pay for the S-300s, he said he did not wish to comment on that, adding that the country "can solve its problems favorably - but our aim is to care for the region and peace in the region, both with the Croatians and with others."
Vucic was also asked about two Serbian nationals kidnapped in Libya in November to say they were alive, and that "citizens can expect, as soon as tomorrow, good news about the case."
A driver and a clerk of the Serbian embassy in Libya, Jovica Stepic and Sladjana Stankovic, were kidnapped by terrorists when a convoy of vehicles they were traveling in was ambushed.