By MATTHEW LEE
AP Diplomatic Writer
WASHINGTON (AP) — The United States and its closest partners are stepping up pressure on Iran to return to stalled nuclear negotiations, warning that it will face greater international isolation, new economic penalties and possibly military action if does not. In a series of high-level meetings this week, U.S., European, Israeli and Arab officials agreed that Iran must be convinced that its continued resistance to rejoining the talks in Vienna will not be ignored or left unpunished. The consensus comes amid growing concerns Tehran isn’t serious about returning to the negotiations. The Biden administration and others have become increasingly pessimistic about the prospects for such negotiations even if they do resume.