China sent an official who was recently removed from the top echelons of power to meet Iranian President Ebrahim Raisi, a sign Beijing is keeping its distance from the Middle Eastern nation as it deals with widespread unrest.

Chinese Vice Premier Hu Chunhua met Raisi in Tehran on Tuesday, the official Xinhua News Agency reported - an encounter that came a day after Iran hanged a second person over long-running protests sparked by the death of a woman in police custody.

Hu's visit comes after Chinese President Xi Jinping visited Saudi Arabia last week in a sign of deepening ties with another major regional partner.

Xi didn't stop in Iran, unlike a previous regional tour in 2016 and the trip was heavily criticized by Iranian lawmakers and officials.

They condemned a joint statement from China and Gulf countries made during Xi's visit which referred to Tehran's "destabilizing regional activities," its nuclear program and its "support for terrorist and sectarian groups," all language reflecting long-held Gulf views.

Aspects of Xi's visit to Saudi Arabia caused "dissatisfaction" within Iran's government, Raisi told Hu Tuesday, the state-run Islamic Republic News Agency reported. Raisi "demanded compensation" for the joint statement, it said, without giving further details.

That joint statement also pledged support for efforts by the United Arab Emirates to open formal discussions about the sovereignty of three islands in the Persian Gulf that have been governed by Iran since 1971, an especially sensitive topic for Tehran.

China is a vital trade partner for Iran as it remains the only customer of oil exports heavily sanctioned by the US. It's also one of the main negotiating powers in the stalled talks to revive the 2015 nuclear deal.

Hu told Iranian officials that China "will not waver in its determination to develop their comprehensive strategic partnership," Xinhua said. "China firmly supports Iran in opposing external interference and safeguarding its sovereignty, territorial integrity and national dignity," it cited Hu as saying.

Some moderate newspapers in Iran have reacted to the Xi visit and joint statement by questioning Iran's dependence on China. One publication - Arman-e Emrooz - even expressed support for Taiwanese independence in a front page headline.

The Islamic Republic is currently gripped by anti-government protests that have been posing a major challenge to its theocratic leadership. A crackdown by authorities has triggered widespread condemnation and sanctions from the West.

China has also faced strong levels of public dissent recently over its Covid Zero policy including rare calls for Xi to step down. He responded to the protests by swiftly moving to dismantle core parts of the strategy.

The Xinhua report didn't mention Iran's protests, which erupted in September when Mahsa Amini, a 22-year-old woman arrested for allegedly flouting Islamic dress codes, died in the custody of so-called morality police. London-based rights group Amnesty International said last week it had identified 44 children killed by Iran's security forces in the unrest.

"The domestic situation is an internal affair of Iran," Chinese Foreign Ministry spokesman Wang Wenbin said Wednesday at a regular press briefing in Beijing, adding he wouldn't offer further comment on it.

He avoided a question on whether China was considering any changes to its diplomacy with Iran.

Hu was once seen as a potential leader of China, but failed to keep a seat on the Politburo or gain promotion at a twice-a-decade congress of the ruling Communist Party in October that saw Xi pack top decision-making bodies with allies.

China itself experienced its most widespread protests in decades late last month. Those demonstrations were largely focused on Xi's stringent policy for containing Covid-19, though some people did call for Xi to step down after a decade in power.