Iran's Supreme Leader Ayatollah Ali Khamenei has called on Iran's armed forces to boost their defence capacities but ruled out chances of war breaking out.
On Saturday, Iran announced plans to increase its missile capacity and acquire modern fighter jets and submarines as part of efforts to expand its military.
The announcement came in the wake of a decision by the United States to withdraw from a multinational nuclear deal with Iran and reimpose sanctions against it.
"Ayatollah Khamenei emphasised that based on political calculations there is no likelihood of a military war but added that the armed forces must be vigilant ... and raise their personnel and equipment capacities," Khamenei's official website quoted him as telling commanders of Iran's air defence forces on Sunday.
Saturday's news of the military development plans came a day after Tehran rejected a French call for negotiations on future nuclear plans, its ballistic missile arsenal and its role in ongoing regional conflicts.
Earlier this week, Iranian lawyers asked the International Court of Justice to order the US to lift the sanctions, saying the measures - which are damaging Iran's already weak economy - violate terms of a little-known 1955 friendship treaty between the two countries.
On Wednesday, in a meeting with President Hassan Rouhani and his cabinet, Khamenei warned that Iran might abandon its nuclear deal with world powers, casting doubt on the ability of European states to save the accord following the US withdrawal.
He said Iran "should give up hope on [Europe] over economic issues or the nuclear deal", according to his website.
"The nuclear deal is a means, not the goal, and if we come to this conclusion that it does not serve our national interests, we can abandon it," he was quoted as saying.
Iran would never negotiate with "indecent and confrontational" US officials on a new agreement, Khamenei added.
In August, Iran unveiled a new domestic fighter jet, reportedly the first to be "100-percent indigenously made".
At the time, Iranian President Hassan Rouhani said the country's military strength was designed to deter enemies and create "lasting peace", adding it was also what deterred Washington from attacking it.
