At a summit in Washington, D.C., on Friday, President Joe Biden met with British Prime Minister Keir Starmer to discuss, in part, the increasing ties between Russia and Iran. According to Western officials, they described the development that Russia has become more cooperative with Iran’s goals of making a nuclear weapon as worrying and an escalation of already troubling ties.

Secretary of State Antony Blinken expressed this concern earlier this week during a visit to London, describing the ties between the two countries as a “two-way street.”

“For its part, Russia is sharing technology that Iran seeks — this is a two-way street — including on nuclear issues as well as some space information,” he said.

The increased concern follows a report from the United Nations’s nuclear watchdog that indicated Iran increased its stockpile of enriched uranium just below weapons-grade level by nearly 50 pounds over the stretch of May to August. According to the International Atomic Energy Agency, Iran has a little over 360 pounds of enriched uranium at near weapons-grade level, and it would only need about 90 pounds of that uranium to be at weapons-grade level to create a nuclear weapon.

The U.S. said on Sept. 10 that Iran sent Russia shipments of its Fath 360 ballistic missiles, which are considered short-range missiles and can travel as far as 75 miles. Shortly after, the U.S. announced sanctions against Iran Air, the regime’s flag carrier, with France, Germany, and the U.K. following suit.

Foreign ministers of the G7 condemned the missile shipments in a statement on Saturday, saying the move “represents a further escalation of Iran’s military support to Russia’s war of aggression against Ukraine.”

“Iran must immediately cease all support to Russia’s illegal and unjustifiable war against Ukraine and halt such transfers of ballistic missiles, UAVs and related technology, which constitute a direct threat to the Ukrainian people as well as European and international security more broadly,” the statement added.