Russia on Monday called Iran “our important partner” while failing to explicitly deny reports that it received short-range ballistic missiles from Tehran to use in its war against Ukraine.

The comments were the latest indication of increased coordination between Moscow and Tehran, a burgeoning partnership that has alarmed Western countries including the US.

CNN and the Wall Street Journal reported last week that Iran had transferred the missiles to Russia, as Moscow continues to wage war in Ukraine after its 2022 invasion.

Kremlin spokesman Dmitry Peskov on Monday said of the reports that “this kind of information is not true every time.” However, he quickly touted Russia’s relationship with Iran and said the relationship would continue to grow.

“Iran is our important partner,” he told reporters. “We are developing our trade and economic relations. We are developing our cooperation and dialogue in all possible areas, including the most sensitive ones, and will continue to do so in the interests of the peoples of our two countries.”

Meanwhile, Iranian officials adamantly denied reports of supplying Russia with missiles.

“We strongly reject allegations about Iran’s role in sending weapons to one side of the war and we assess these allegations as politically motivated by some parties,” Iranian foreign ministry spokesman Nasser Kanaani said at a press conference.

Separately, a senior commander in Iran’s Islamic Revolutionary Guard Corps, an internationally designated terrorist organization, refuted the reports.

“No missile was sent to Russia and this claim is a kind of psychological warfare,” Fazlollah Nozari was quoted by the Iranian Labour News Agency as saying. “Iran does not support any of the parties to the Ukraine-Russia conflict.”

Despite the denials, Ukraine’s foreign ministry said on Monday it had summoned a senior Iranian diplomat to warn of “devastating and irreparable consequences” for bilateral relations if the missile reports were correct.

“Iran must completely and definitively stop providing weapons to Russia in order to prove with actions, not words, the sincerity of its political leadership’s statements about non-involvement in fueling the Russian war machine of death,” the ministry said in a statement on Saturday.

US officials expressed alarm over the idea of Iran supplying Russia with missiles.

“Any transfer of Iranian ballistic missiles to Russia would represent a dramatic escalation in Iran’s support for Russia’s war of aggression against Ukraine,” the White House said.

CIA Director William Burns warned of the growing and “troubling” defense relationship between Russia, China, Iran, and North Korea while speaking at a public event in London over the weekend. He said their increased coordination and cooperation threatened not only Ukraine but also Western allies in the Middle East.

The European Union (EU) described as “credible” information provided by allies indicating Iran has supplied short-range ballistic missiles to Russia to help Moscow wage war in Ukraine.

“We are aware of the credible information provided by allies on the delivery of Iranian ballistic missiles to Russia,” EU spokesman Peter Stano said. “We are looking further into it with our member states and, if confirmed, this delivery would represent a substantive material escalation in Iran’s support for Russia’s illegal war of aggression against Ukraine.”

Stano added that the EU “will respond swiftly and in coordination with international partners, including with new and significant restrictive measures against Iran.”

Western and Ukrainian officials have dismissed denials of Iranian weapons transfers in the past. Russia has been receiving Iranian-made Shahed drones since 2022 and using them against Ukraine, according to analysts and government officials.

Reuters and other media outlets also reported earlier this year that Iran sent ballistic missiles to Russia for use against Ukraine, indicating the latest reported missile transfer wasn’t the first.

Warming ties between Moscow and Tehran have extended beyond military matters. For the past two years, Iran and Russia have been working on a major comprehensive bilateral agreement to strengthen cooperation in a wide array of areas. Officials from both countries have said in recent months that the deal will be signed in the near future without elaborating.