Two explosions at a road junction in the centre of the Turkish capital Ankara have killed at least 95 people and injured nearly 200 others, the office of the prime minister has said.
The first blast occurred at around 10am (07:00 GMT), with the second following shortly after, during a peace rally on Saturday organised by several leftist groups, including the pro-Kurdish Peoples' Democratic Party (HDP).
Authorities are exploring the possibility that the blasts may have been caused by two suicide bombers.
Prime Minister Ahmet Davutoglu announced three days of national mourning during a televised press conference on Saturday afternoon.
"We have to stand together against terrorism to defend our country," Davutoglu said, adding that the target of the attack was Turkish unity, democracy and stability.
"We are confident that there is no single citizen who doesn't share the deep sorrow for those who have lost their loved ones in these attacks."
In a statement, the White House said US President Barack Obama had spoken by phone with Recep Tayyip Erdogan, his Turkish counterpart, to convey his condolences.
"The president conveyed his deepest personal sympathies for those killed and injured in these heinous attacks, and affirmed that the American people stand in solidarity with the people of Turkey in the fight against terrorism and shared security challenges in the region," the statement said.
No group has claimed responsibility for the explosions.
A video on social media showed the moment of one explosion: young people were dancing and waving banners as a massive fireball erupts.
The explosions occurred near a train station where people were gathering for a peace march to protest against the conflict between the state and Kurdish fighters in southeast Turkey.
At a news conference in Ankara earlier on Saturday afternoon, the Turkish health minister said that at least 186 people were injured, including 28 who are in intensive care.
Video footage on social media showed several bodies lying on the ground, as survivors tried to attend to the wounded.
Faruk Bildirici, a Turkish journalist who was attending the rally, told Al Jazeera that he was only metres away from the blasts and there were only seconds between the two attacks.
|People react on the multiple explosions that killed many demonstrators in Ankara [EPA]
"Some people were crying and shouting out condemning the attack, some - particularly members of the Turkish Medical Association - were trying to help the wounded." he said.
"I have seen people using banners trying to cover dead bodies and striving to carry the wounded, again with large banners. There were no ambulances or police at the scene.
"This gathering was to deliver a message of peace, democracy and brotherhood in Turkey. This attack prevented people from delivering this message."
Demonstrators angered by the attack on their fellow activists shouted "police murderers!" at the scene of the blasts but were then dispersed as the security forces intervened.
"We are faced with a huge massacre. A barbaric attack has been committed," said the HDP's leader Selahattin Demirtas.
"I strongly condemn this heinous attack on our unity and our country's peace," Erdogan said in a statement posted on the presidency's website.
"No matter what its origin, aim or name, we are against any form of terrorist act or terrorist organisation. We are obliged to be against it together."
|Demonstrators confront riot police following the deadly explosions [Reuters]
The attack came with Turkey on edge ahead of November 1 polls and a wave of unrest over the past few months.
An attack in the predominantly Kurdish town of Suruc on July 20 targeting pro-HDP activists and blamed on Islamic State of Iraq and the Levant (ISIL) fighters killed 32 people and wounded 100 others.
The armed Kurdistan Workers' Party (PKK) accused Ankara of collaborating with ISIL and resumed attacks on the Turkish security forces after observing a two-year ceasefire.
Over 140 members of the security forces have since been killed while Ankara claims to have killed over 1,700 Kurdish fighters in weeks of bombardments of PKK targets in southeast Turkey and northern Iraq.
Hours after the blasts in Ankara, the PKK called for a unilateral ceasefire in its fight against the Turkish state "unless they or the Kurdish people are attacked", according to a statement carried by Kurdish news agencies.
The statement was released by the Group of Communities in Kurdistan (KCK) and did not reference Saturday's attack in Ankara.
The move was widely expected as analysts said the PKK hoped it would boost the HDP's score in the upcoming election.
Additional reporting by Umut Uras
|The attack came with Turkey on edge ahead of November 1 polls and a wave of unrest over the past few months [EPA]
Source: Al Jazeera And Agencies