Amid a stalled fifth round of negotiations in Rome, Iran has grown increasingly pessimistic about the prospects of reaching a deal with the United States. Tehran has responded to reported Israeli strike preparations with warnings of retaliation and appeals to the United Nations.

Iran’s top diplomat is insisting that Tehran will never stop enriching uranium, further underlining the Islamic Republic’s red line in negotiations with the United States over its rapidly advancing nuclear program.

This week, the Islamic Republic announced the appointment of Abdolreza Rahmani Fazli as its new ambassador to Beijing. Who is Fazli? What does the appointment mean for the Iran-China relationship?

TEHRAN, Iran — Iran’s top diplomat insisted Wednesday that Tehran will never stop enriching uranium, reinforcing the Islamic Republic’s hard line ahead of a new round of indirect talks with the United States over its fast-advancing nuclear program.

Ayatollah Ali Khamenei said Tehran won’t seek permission from anyone to enrich uranium and called American statements “nonsense.”