The death of Fahd in a Riyadh hospital was announced on Monday. He was believed to be 83-years old and suffering from pneumonia.
Egyptian President Hosni Mubarak, who called for the Arab summit in Sharm al-Shaikh to discuss the threat of regional terrorism after deadly bombings last month in the Egyptian resort, ordered three days of mourning nationwide.
"The kingdom has lost an honourable son and one of its dearest leaders... History will remember the great and numerous achievements he accomplished for the sake of the holy sites, his people and his nation," a statement said.
Jordan's King Abdullah, who was on his way to London for talks with British Prime Minister Tony Blair when Fahd's death was announced, decreed a 40-day period of mourning at the royal court.
"The Arab and Muslim world has lost an exceptional leader who did not spare any effort in order to unify Arab and Muslim ranks and defend their identity," King Abdullah said in a message of condolence.
"The Arab and Muslim world has lost an exceptional leader who did not spare any effort in order to unify Arab and Muslim ranks and defend their identity"
Jordan's King Abdullah
In Beirut, the government ordered three days of mourning and the closure of public buildings on Tuesday to "honour the memory of a great man who always gave support to Lebanon".
President Emile Lahoud expressed his profound grief and said the death of Fahd, credited with helping to end Lebanon's civil war was a "great loss for the Arab and Muslim world".
A three-day mourning period was also declared by the Palestinian Authority, which recalled Fahd as a stout defender of the Arab and Palestinian people.
"His death is a loss to the millions of Arabs and Muslims around the world. He was a leader who spent his life in defence of Arab causes and particularly on the Palestinian issue," a statement from Prime Minister Ahmad Qurei's office said.
Saudi neighbour Yemen also expressed sadness at the death of Fahd.
"It is a great loss for Yemen, Saudi Arabia and the Arab and Muslim national. King Fahd's death will have repercussions on Arab and Muslim action," Yemeni Foreign Minister Abu Bakr al-Kurbi said in Cairo.
A Saudi man closes his shop in
Riyadh as the country mourns
Pakistan will also observe a week of national mourning, during which the national flag will fly at half-mast, the Foreign Ministry said on Monday.
President Pervez Musharraf, expressing his and the country's condolences in a televised address, said: "In his death, Pakistan and indeed, the entire Muslim world has lost a statesman of high calibre."
British Prime Minister Tony Blair described Fahd a man of great wisdom and a "good friend" of Britain.
"King Fahd was a man of great vision and leadership who inspired his countrymen for a quarter of a century as king, and for many more before that," Blair said in a statement.
In Paris, the French presidential palace sent its condolences to Saudis, praising Fahd as a respected ruler and a friend of France.
"During his reign, Fahd was above all concerned about the security of his people," the statement said.
A Saudi man kisses a television
showing a picture of King Fahd
Russian President Vladimir Putin expressed sadness, saying Fahd had been a strong leader.
"Thanks to his personal efforts, Saudi Arabia achieved substantial success and significant strengthening of its international position," Putin said.
German Chancellor Gerhard Schroeder expressed his condolences, paying tribute to his "balanced policies" in the Middle East.
"His balanced policies and mediation in the Middle East brought him and the kingdom of Saudi Arabia respect and recognition around the world." Schroeder said in a telegram addressed to the Saudi monarch's successor, Abdullah.