Thousands of people participated in events to mark an official three-day mourning period in the Turkish capital on Sunday, following the twin blasts at a peace rally of leftist and pro-Kurdish activists the day before.
The attack - the country's deadliest in years - killed at least 95 people and wounded hundreds of others. The death toll is likely to rise, with dozens of people still in intensive care.
Clashes also broke out on Sunday, including reports of tussles between pro-Kurdish mourners and police near the site of the blasts. The leaders of a pro-Kurdish party, who were there at the scene, accused the government of not doing enough to stop the blasts.
The funeral of one victim, a member of the Alevi religious community, also drew thousands. According to the Associated Press news agency, the crowd raised their fists in solidarity in front of the place of worship where the funeral service was held before denouncing President Recep Tayyip Erdogan.
An official period of mourning
Prime Minister Ahmet Davutoglu declared three days of mourning on Saturday after the attacks, suggesting that Kurdish rebels or "Islamic State" (IS) group militants were to blame. No one has so far claimed responsibility for the bombings, which Davutoglu said bore "strong signs" of having been carried out by one or more suicide attackers.
Leaders from around the world have condemned the attacks. German Chancellor Angela Merkel expressed "sadness and dismay," calling the attacks "particularly cowardly acts that were aimed directly at civil rights, democracy and peace."
"It is an attempt at intimidation and an attempt to spread fears," she said, adding: "I am convinced that the Turkish government and all of Turkish society stands together at this time with a response of unity and democracy."
US President Barack Obama, in a telephone call to President Erdogan, was reported to have pledged continued US support to Turkey in the fight against terrorism.
And NATO Secretary General Jens Stoltenberg said there could be "no justification for such a horrendous attack on people marching for peace... All NATO allies stand united in the fight against the scourge of terror."
The attacks come at a tense time for Turkey, which is currently embroiled in fresh offensives against rebels from the Kurdistan Workers' Party (PKK) that have left hundreds dead. Saturday's peace rally was to have called for an end to the renewed violence and for increased democracy in Turkey.
Following the attacks on Saturday, the PKK issued a statement that it was halting hostilities to allow the country's November 1 election to proceed in peace. The government, however, said late on Friday it would continue its operations against the group until it disarms.
The upsurge in violence in recent months was triggered by a bombing attack in July on activists supporting the pro-Kurdish Peoples' Democratic Party (HDP) in the town of Suruc in which more than 30 people were killed.
The PKK accused Ankara of supporting IS jihadists suspected of being behind that attack, and resumed violence against security forces, breaking a two-year ceasefire.
The HDP leader, Selahattin Demirtas, also blamed Ankara for involvement in Saturday's attacks, saying they had been carried out by a "murderous state."
Erdogan has been accused by many of increasing tensions with the Kurds in a bid to bring voters back to the ruling Justice and Development Party, or AKP, after it lost its majority in a June election after a decade of single-party rule owing largely to gains by the pro-Kurdish party.
Tens of thousands of people marched in Istanbul and other Turkish cities on Saturday evening to denounce the bombings, and there were also protests in Paris, Strasbourg and Marseille in France, and Zurich in Switzerland.
tj,blc/jlw,rc (AFP, AP)