Sultan Haitham Bin Tariq Al Said is sworn in before the royal family council in Muscat on Saturday. Reuters

Oman's new royal ruler pledged on Saturday to follow the non-interference policy that made the kingdom a vital regional mediator under his late cousin Sultan Qaboos who reigned for half a century.

Haitham Bin Tariq, the culture minister, was sworn in shortly after modern Oman's founding father was laid to rest after his death on Friday at the age of 79.

"We will follow the path of the late sultan," Haitham, 65, said in his first public speech which was aired live on state television.

He expressed support for "our country's foreign policy of peaceful living among nations and peoples... and not interfering in the internal affairs of others, respecting nations' sovereignty and international cooperation."

"Haitham Bin Tariq was sworn in as the new sultan of the country... after a meeting of the family which decided to appoint the one who was chosen by the sultan," the government said in a tweet.

Haitham, a sports enthusiast, was appointed to lead the heritage and culture ministry in the mid-1990s and also serves as head of the committee for Oman's "Vision 2040", a roadmap for social and economic reform.

Sultan Qaboos was laid to rest at the royal cemetery on Saturday after his coffin, draped in the Omani flag, was driven through the streets of the capital Muscat.

Thousands of people, including members of the royal family and state officials, were present for prayers at the main mosque which is named after the sultan.

The royal court announced a mourning period that will see businesses and government offices close for three days.

As the Gulf's discreet go-between, Oman played a role in Iran's 2015 nuclear deal with world powers while preserving its membership in the Saudi-led Gulf Cooperation Council (GCC).

"He was a stable force in the Middle East and a strong US ally. His Majesty had a vision for a modern, prosperous, and peaceful Oman, and he willed that vision into reality," former US president George W. Bush said in a message of condolence.

The late sultan's standing was recognised with warm tributes from across the world, including from Iran's Foreign Minister Mohammad Javad Zarif who said in a tweet written in Arabic that his death was a "loss for the region."

British Prime Minister Boris Johnson also recalled a meeting with Qaboos where he was "struck by his commitment to peace and understanding between nations and between faiths."

"He leaves a profound legacy, not only in Oman but across the region too," Johnson said.

Agence France-Presse