The international community expressed alarm and concern after Iran launched missile attacks on the United States' military bases in Iraq on Wednesday, spiking fears of a full-blown conflict in the Middle East.

Iran has said that it attacked the military bases in retaliation to the US drone strike on Iranian commander Qassem Soleimani that killed him last week. Iraq’s military said 22 missiles were launched on the Ain al-Asad air base in western Anbar province and a base in the Iraqi Kurdish capital Erbil, causing no casualties among Iraqi forces.

With US President Donald Trump set to make a statement soon, countries urged for calm and restraint.

China hopes for matters to cool off

China's foreign ministry expressed concern about the spike in tensions in the Middle East and said that it hopes matters can swiftly cool off.

Following the attacks, Foreign Ministry spokesman Geng Shuang told reporters that Beijing has called for restraint by all sides and is in close consultation with the governments involved, including at the UN and through China's embassy in Baghdad.

Russia warns of nuclear war

Russian lawmaker Vladimir Dzhabarov warned that a conflict between the US and Iran might lead to a nuclear war.

"Reciprocal strikes by the US and Iran may lead to an all-out war in the region," Dzhabarov said. "If Washington sees that it can't achieve its goals, there's a danger of a nuclear war."

He said that the UN Security Council should get involved to prevent further escalation in the Middle East.

Germany condemns Iranian attacks

Germany condemned the Iranian missile strike at bases in Iraq used by US forces. Defense Minister Annegret Kramp-Karrenbauer said that the German government "rejects this aggression in the sharpest possible terms".

"It's now particularly up to the Iranians not to engage in further escalation," she told German public broadcaster ARD.

Britain tells Iran not to repeat 'reckless' attacks

The United Kingdom too condemned the attack and urged Iran to "not to repeat these reckless and dangerous attacks".

“We, of course, condemn the attack on Iraqi military bases hosting coalition forces. Iran should not repeat these reckless and dangerous attacks but must instead pursue urgent de-escalation,” British Prime Minister Boris Johnson told the UK parliament.

British Foreign Secretary Dominic Raab had earlier told Iran to "instead pursue urgent de-escalation".

"A war in the Middle East would only benefit Daesh (the militant Islamic State group) and other terrorist groups. Coalition forces are in Iraq to train local forces to fight the extremists," Raab had said.

France urges de-escalation on 'top priority'

France, like its fellow European Union members, also condemned the Iranian strikes and said de-escalation is the top priority as tensions mount further between Tehran and Washington.

"The priority is more than ever for a de-escalation," Foreign Minister Jean-Yves Le Drian said in a statement. "France remains determined to work to ease tensions and is in contact with all the parties to encourage restraint and responsibility."

The EU, however, said that it will spare no efforts in its attempts to keep alive an international deal preventing Iran from developing atomic weapons.

UAE hopes for de-escalation

Meanwhile, the energy minister of the United Arab Emirates said that he sees no immediate shortages in oil supplies, but that the Organization of the Petroleum Exporting Countries will be called in if there is an issue.

"The situation is not currently a war situation," Suhail Al-Mazrouei told reporters. "We are all hoping for de-escalation. I think wisdom will prevail despite the tension."

He said that the flow of oil has been maintained even in past times of war, adding: "So let's not exaggerate what's happening. There is no risk that we have seen to the Strait of Hormuz or the movement of oil yet."

He was referring to the narrow waterway between the Arabian Peninsula and Iran through which 20 per cent of the world's oil passes through.

His comments came as Brent crude oil jumped to around $70 a barrel amid heightened concerns over tensions between Iran and US.

Japan to urge nations to improve relations

Japan said that it will urge governments to do their utmost to help ease tensions following Iranian missile attacks.

Japanese Chief Cabinet spokesman Yoshihide Suga said that his government will coordinate with the related governments to "collect intelligence while we ensure the safety of Japanese citizens in the region".

He added: "Japan will also urge all related nations to do their utmost diplomatic effort to improve the relations."

Yoshihide said Japan remained on track to soon deploy a warship to the Gulf to help safeguard Japanese vessels and oil tankers transiting the area.

Nato tells Iran to 'refrain from further violence'

Nato chief Jens Stoltenberg joined Western countries in condemning Iranian rocket attacks on Iraqi bases housing US troops.

"I condemn the Iranian missile attacks on US and coalition forces in Iraq. Nato calls on Iran to refrain from further violence," Stoltenberg tweeted.

"Allies continue to consult and remain committed to our training mission in Iraq."

A Nato official said that there were no casualties among the troops on its training mission in Iraq, though on Tuesday the alliance said it was moving some personnel out because of the increased danger following Soleimani's killing.