After U.S. strikes on Iranian nuclear facilities over the weekend, their response has been swift. Below is a snapshot of key U.S. allies and partners’ reactions amid fears of wider regional escalation:

Europe: Cautious, Diplomatic and Assertive United Kingdom PM Keir Starmer recently called on Iran to return to the negotiating table while emphasizing stability over war as the primary goal (Sources: Reuter’s, Ap News and Euro News). For more details please check these sources of news: Reuter’s, Ap News and Euro News +15
London closed and evacuated its embassy in Tehran amidst rising tensions, yet officials confirmed no military support was offered to either U.S. or Israeli operations, according to The Times (thetimes.co.uk).
German and French Foreign Ministers Held Urgent Talks European foreign ministers from Britain, Germany, and France convened urgent talks in Geneva this weekend calling on Iran to limit its nuclear program while warning that direct U.S. strikes could undermine diplomacy (eurosnews.com and FT both provide coverage)
President Emmanuel Macron reiterated his position that Iran must not obtain nuclear capabilities while calling for more diplomatic dialogue and engagement between Tehran and Europe, according to Euronews and The Guardian reports.
Germany’s Chancellor Friedrich Merz applauded Israel’s attacks, applauding them as a way of weakening Iran; Iran responded by summoning Germany’s ambassador (according to Reuters.com and en.wikipedia). This incident happened just prior to an international crisis over Iraq which started in March 2008. United Kingdom officials condemned these attacks but still supported Israel due to it having weakening effects.
Starmer convened an emergency COBRA committee, emphasizing his view that Iran must never acquire nuclear weapons and advocating a diplomatic resolution, according to The Guardian and Euronews reports.
The British government made clear it did not support military action by Israel or the U.S., discouraging further military escalation by discouraging further use of force by both parties and discouraging further military escalation by Canada and other G7 Nations.
At the recent G7 summit in Canada, world leaders affirmed Israel’s right to self-defense while condemning Iran as a source of regional instability, while encouraging other G7 members to utilize diplomatic channels should tensions mount.

Russia and China: Strategic Alarm
Russia has issued a strong warning that U.S. strikes bring the world “millimeters” away from nuclear catastrophe and has offered to mediate peace through Russia’s longstanding ties with Tehran, suggesting they might offer mediation services towards peace-making efforts by offering to mediate peace through Moscow’s mediating peace through aljazeera.com, euronews.com, NewYorkPost.com and Time.com as possible platforms.
China and Iran share close economic ties, yet Beijing has refrained from publicly criticizing the United States. Instead, Beijing has encouraged restraint and sought dialogue to protect energy supplies.

United Nations Secretary-General Antonio Guterres expressed alarm over the strikes and warned of their potential “catastrophic effects” for civilians reuters.com
APnews.com He issued calls for de-escalation and diplomatic engagement.