Kazakhstan's Senate chairman Kassym-Jomart Tokayev takes the oath as Kazakh interim president during a ceremony in Astana, March 20, 2019.
Kazakhstan's Senate chairman Kassym-Jomart Tokayev takes the oath as Kazakh interim president during a ceremony in Astana, March 20, 2019.

China on Wednesday welcomed the new president of Kazakhstan as an "old friend" after the sudden resignation of veteran strongman Nursultan Nazarbayev.

Nazarbayev, the only leader an independent Kazakhstan has ever known, shocked the nation Tuesday with his resignation after nearly three decades in power.

"China understands and supports President Nazarbayev's decision," said foreign ministry spokesman Geng Shuang.

Kazakhstan's President Nursultan Nazarbayev writes
FILE - Kazakhstan's President Nursultan Nazarbayev writes during a televised address to announce his resignation, in Astana, Kazakhstan, March 19, 2019.

"Since we established diplomatic ties 27 years ago, President Nazarbayev has been committed to friendly relations," Geng told reporters, noting the oil-rich nation will achieve new progress under the acting president Kassym-Jomart Tokayev.

Observers widely expect Nazarbayev, 78, to retain control from behind the scenes. He came to power when Kazakhstan was still a Soviet republic.

He passed the presidency to the chairman of the senate, loyalist Kassym-Jomart Tokayev, 65, a former prime minister and career diplomat who was sworn in Wednesday.

"The acting President Tokayev is an old friend and good friend of the Chinese people," Geng said.

Kazakhstan, which shares a border with China's restive Xinjiang region, has been on diplomatic tiptoes since its major trading partner began to send ethnic Kazakhs to internment camps under its anti-extremism policy.

Earlier this month, authorities in Kazakhstan arrested a Xinjiang rights activist, who had campaigned for victims of China's security crackdown in the region, and charged him with inciting inter-ethnic hatred.