Iran has officially invited Saudi Arabia's king to visit the country, an Iranian Foreign Ministry spokesperson said on Monday, after the two regional rivals agreed to end years of hostility following a China-brokered agreement in March.

After years of bad relations that fueled proxy conflicts across the Middle East, where Tehran and Riyadh backed opposite sides from Yemen to Syria, the Shi'ite revolutionary Iran and the Sunni-led Kingdom reached an agreement to end a seven-year diplomatic rift.

"Iranian President (EbrahimRaisi) has sent an invitation to the Saudi king in return for an invitation by Riyadh for him," Nasser Kanaani told a televised news conference.

Technical delegations from both countries are preparing to officially reopen their missions, and Tehran said these missions would restart their activities by May 9, Iran's semi-official Tasnim News agency reported.