Iran has test-fired two long-range missiles which defence analysts say are capable of hitting Israel or US bases in the Gulf region.
The state-sponsored Press TV news channel said that the Shahab 3 and Sejil missiles were fired on Monday, the second day of military exercises by Iran's Revolutionary Guard forces.
Britain, France and the European Union all expressed their "concern" after the tests, which come just days before Tehran is due to meet the five permanent members of the UN Security Council, plus Germany, to discuss its nuclear programme.
"We call on Iran to choose the path of co-operation rather than confrontation, by immediately ceasing these deeply destabilising activities," a statement from the French foreign ministry said.
But Russia, which has repeatedly resisted attempts to increase sanctions against Iran over its nuclear enrichment work, urged calm from the negotiating powers.
"Now is not the time to succumb to emotions. It is necessary to calm down and, above all, to start up an effective negotiation process," the Interfax news agency quoted a Russian foreign ministry source as saying.
Iranian officials have said the Shahab 3, which was last tested in mid-2008, and Sejil can both travel about 2,000km.
"Iranian missiles are able to target any place that threatens Iran," Abdollah Araqi, a senior Revolutionary Guard commander, was quoted as saying by the semi-official Fars news agency.
Earlier on Monday, Iran test-fired Shahab 1 and Shahab 2 missiles capable of hitting targets between 300km and 700km away.
The missile tests come at a time of increased tension after last week's disclosure by Tehran that it is building a second uranium enrichment plant.
Alireza Ronaghi, Al Jazeera's correspondent in Tehran, said: "There are two solutions about Iran: one would be sanctions and the other would be military action. So [with regard to] sanctions, Iran is trying to prove that sanctions have not worked on the uranium enrichment programme.
"And as far as the military option is concerned, Iran is showing off missiles trying to say that a military option is not going to be viable; it's not going to be a hit-and-run.
"Iran will retaliate and it will not just limit itself to the countries that have led those attacks; it will be a wide range retaliation. This is the message that Iran is sending."
Iran stages regular military manoeuvres in the Gulf, showcasing its long- and medium-range missiles as well as other weaponry.
Theodore Karasik, a defence analyst based in Dubai, told Al Jazeera: "The range [of the missiles], of course, is critical and if they decide to fire the missiles, they would be able to hit various targets based on their selected need.
"The question becomes the accuracy of these missiles, and the earlier series of these Shahabs were notoriously inaccurate. In military parlance, that's called 'circular error probability'. This raises the issue of the sophistication of Shahab 3."
Javier Solana, the European Union foreign policy chief, said that the missile tests placed the October 1 meeting over Iran's nuclear programme "in a new context".
Western powers, along with Israel, suspect Iran wants to use its nuclear technology to make weapons.
Following Friday's tests, Ahmad Vahidi, the Iranian defence minister, had warned Israel against any attack on the Islamic republic.
"If this happens, which of course we do not foresee, its ultimate result would be that it expedites the Zionist regime's last breath," he said in an interview broadcast on state television.
Tehran insists its nuclear programme is aimed at generating electricity for civilian purposes.
Source: Al Jazeera and agencies