World leaders paid homage to Sultan Qaboos of Oman, who died at the age of 79, as a wise and moderate leader and a champion of Arab and Islamic nations.

Here are some of the main tributes by world leaders.

US President Donald Trump called the sultan a friend to America who worked for peace in the Middle East.

"As the longest-serving leader in the Middle East, Sultan Qaboos brought peace and prosperity to his country and was a friend to all," Trump said in a statement.

"His unprecedented efforts to engage in dialogue and achieve peace in the region showed us the importance of listening to all viewpoints. Sultan Qaboos was a true partner and friend to the United States, working with nine different American presidents," Trump said.

A joint European Commission-European Union statement praised Qaboos's "sense of pragmatism and his unparallelled savoir-faire".

"His vision steered a foreign policy that placed Oman among the European Union's closest partners, in a region mired in conflict and gripped by tensions," he added.

The sultan was "committed to spreading messages of peace, understanding and coexistence in the region and globally, earning the respect of his people and those in the region and beyond," said Stephane Dujarric, spokesman for the UN secretary-general.

"He was a great leader who worked tirelessly to promote peace and stability in our region," wrote Israeli Prime Minister Benjamin Netanyahu.

The late sultan "made great efforts for the welfare and development of Oman as well as being an important figure in the politics of the region", Turkey's President Recep Tayyip Erdogan tweeted.

Sultan Qaboos's death was "a loss for the region", said Iran's Foreign Minister Mohammad Javad Zarif, tweeting in Arabic.

Congratulating Oman on its choice of His Majesty Haitham bin Tariq as his successor, he hoped the two countries' relations would continue to grow.

(FILES) In this file photo taken on May 31, 1981 Oman's Sultan Qaboos bin Said (pictured 1981) died January died January 10, 2020 at the age of 79
(FILES) In this file photo taken on May 31, 1981 Oman's Sultan Qaboos bin Said (pictured 1981) died January died January 10, 2020 at the age of 79 LEHTIKUVA / -

Qaboos "led the sultanate of Oman on a path of progress and advancement and managed with great wisdom and sophistication to create a distinguished place for the country among Arab states" said Syrian president Bashar al-Assad

Iraqi President Barham Saleh paid tribute to the late sultan's "moderation and wisdom and the ability to control differences in the interest of the development and progress of our countries and region".

"The Gulf, Arab and Islamic nations lost a very important figure and leader," said Kuwait's Emir Sheikh Sabah al-Ahmad al-Sabah.

The leaders of Saudi Arabia and Qatar also offered their condolences.

Qaboos was "a constant supporter of Arab and Islamic issues in various situations, and the pioneer of Oman's renaissance", wrote Egypt's President Abdel Fattah al-Sisi.

"Our Arab and Islamic nation lost today, a leader and leader of its finest men," said Palestinian president Mahmud Abbas.

Qaboos "devoted his life to serving his country and people and the issues of the Arab and Islamic nations with wisdom and balance," he added.

"He was an exceptionally wise and respected leader who will be missed enormously," said British Prime Minister Boris Johnson.

During his reign, Sultan Qaboos modernised his country "while respecting its traditions and its values," said French President Emmanuel Macron. "The Omani people lose a man of spirit and culture, at the same time deeply attached to his Omani roots and open to the world, especially to France which he knew well".

Qaboos's death meant "the loss of a good friend for Germany", a statement from President Frank-Walter Steinmeier said.

"Sultan Qaboos was a responsible actor for mutual understanding and compromise in the Middle East and Gulf region. His word was widely heeded".