The Ministry of Home Affairs on Sunday declared that India will observe a day of state mourning on Monday as a mark of respect following the death of Oman’s Sultan Qaboos bin Said. The ministry added that the national flag will be flown at half-mast throughout India on Monday.

The sultan died on Friday and was laid to rest in the Royal Family Cemetery in the city of Bausha the next day. Though the announcement about his death did not mention the cause, Qaboos had been receiving cancer treatment in Europe since at least 2014.

“His Majesty Sultan Qaboos Bin Said Al Said, Sultan of the Sultanate of Oman has passed away on 10.01.2020,” the ministry spokesperson tweeted. “As a mark of respect to the departed dignitary, Government of India has decided that there will be one day’s state mourning on 13.01.20 throughout India.”

“The national flag will be flown at half mast throughout India on the day of mourning and there will be no official entertainment on the day,” the spokesperson added.

The ministry has also sent a communication to all states and Union Territories in this regard, PTI reported.

Prime Minister Narendra Modi had said that the sultan was a true friend of India, while expressing his condolences. “He was a visionary leader and statesman who transformed Oman into a modern and prosperous nation,” he tweeted. “He was a beacon of peace for our region and the world.”

Oman and other Gulf states have declared three days of official mourning for the 79-year-old Qaboos, who had ruled since taking over in a bloodless coup in 1970 with the help of Britain. He was the longest serving Arab leader. His cousin Haitham bin Tariq al-Said was named his successor.

Qaboos was revered in his country for using oil wealth to pull it from poverty. Roads, a port, a university, and a sports stadium are some of the things that bear his name. He was instrumental in bringing together Iran and the United States for covert talks that led to an international agreement about Iran’s nuclear programme, limiting Tehran’s chances developing a nuclear bomb. However, the Donald Trump administration pulled the country out of the deal, and in recent weeks ratcheted up tensions with Iran.