*Calls mount for transparent, independent international inquiry into death of Egypt's first democratically elected head of state
The death of Mohamed Mursi, modern Egypt's first democratically elected head of state, while on trial in a Cairo court, has brought an outpouring of condolences around the Middle East and calls for an investigation into his conditions.
The 67-year-old Islamist, a leading figure in the Muslim Brotherhood, was deposed by the army and jailed in 2013 after barely a year in power.
As his body was buried Tuesday, many condemned harsh prison conditions as a likely cause of his heart attack and blamed current president Abdel Fattah al-Sisi.
The UN human rights office called for an "independent inquiry" into Mursi's death while in state custody.
"Any sudden death in custody must be followed by a prompt, impartial, thorough and transparent investigation carried out by an independent body to clarify the cause of death," said Rupert Colville, spokesman for the United Nations High Commissioner for Human Rights.
Mursi was buried in a small family ceremony, a day after suffering a fatal heart attack in court at a Cairo prison, his sons said.
The Islamist ex-president's death after six years in jail under the military-backed establishment stoked anger among his supporters in Egypt and abroad.
His Muslim Brotherhood, now banned in Egypt, described it as "full-fledged murder" and called for mass gatherings. Egyptian officials denied accusations that Mursi's health had been neglected.
Witnesses in Mursi's home province of Sharqiya said hundreds of residents in the village where he was born had performed prayers for Mursi amid tight security on Tuesday, and afterwards chanted "Down with military rule!". A number of residents were detained, a security source said.
Life appeared normal in the capital, where authorities have cracked down on Islamists and other activists since Mursi's overthrow. Thousands of Muslim Brotherhood members in Turkey took to the streets of Ankara and Istanbul, some of them blaming Egyptian authorities for the death.
Turkish President Recep Tayyip Erdogan attended an Istanbul prayer service for Morsi at the historic Fatih mosque and called the Islamist leader a "martyr".
Here are some of the reactions: His Highness the Amir Sheikh Tamim bin Hamad al-Thani - "We received with deep sorrow the news of the sudden death of former President Dr. Mohamed Mursi. I extend to his family and to the brotherly Egyptian people the deepest condolences."
Rights lawyer Khalid Ali- "Medical negligence and policies of slow death through solitary confinement in prison are all tools to kill.
"Agree or disagree as you wish with Dr. Mohamed Mursi, but what he was subjected to as a human being since his arrest and the conditions he was placed under that ended in his death are crimes that deserve trial and punishment."
Conservative British MP Crispin Blunt, who led a review last year of the detention of Mursi said there should be an independent international probe into his death.
"Dr Mursi's death in custody is representative of Egypt's inability to treat prisoners in accordance with both Egyptian and international law," he said.
He said Cairo "has a duty to explain his unfortunate death and there must be proper accountability for his treatment in custody".
Arab Network for Human Rights Information- "He was not the first victim of human rights violations, but he must be the last."
Ayman Nour, Opposition liberal politician, called Mursi "a martyr who was killed deliberately, slowly, over six years, during which he faced all kinds of abuse and hardship ... Sisi and his regime are fully responsible for the result."
Amr Darrag, Senior member of of Brotherhood's political party- "Mohamed Mursi was deliberately killed with premeditated intent ... Sisi is the murderer and there must be a transparent and independent international investigation."
Moderate Islamist Al-Wasat party- "This great shock is perhaps a reminder of the risk that is posed by negligent medical attention, humanitarian care and denial of visitation faced by a large number of political prisoners, a risk that threatens all of their lives."
Iran's Foreign Ministry- "The Islamic Republic of Iran, while respecting the views of the great and brave nation of Egypt, offers its sympathies over the death of Dr. Mohamed Mursi to the Egyptian people, his family and his loved ones."
Yusuf Qaradawi, Senior Doha-based cleric- "May God have mercy on the patient and calculated Egyptian president, Dr. Mohamed Mursi ... May Allah accept him as a martyr."
Murad Adaylah, head of Jordan's Islamic Action Front part- "This martyr ... was killed ... by the Egyptian regime forces, the forces of the coup who prevented him from getting his medicine and carried out a crime against Mursi.
"What is happening now is stirring up the nation and the Egyptian people. Mohamed Mursi is the martyr of freedom, the martyr of legitimacy, the martyr of democracy, the martyr of the free elections."
Amnesty International -Egypt has "an appalling track record of detaining prisoners in prolonged solitary confinement and in dire conditions as well as subjecting prisoners to torture and other ill-treatment".
Tawakkol Karman, Joint recipient of Nobel Peace Prize- "I mourn, for myself and all the free people of the world, the death of a great striver on the path of freedom."