(CNN) Pro-Kurdish lawyer Tahir Elci, president of the Diyarbakir Bar Association in southeastern Turkey and a leading human rights defender, was killed while making a press statement Saturday.

The statement in the Sur district of the predominantly Kurdish Diyarbakir province was intended to call attention to damage done to the 1,500-year-old Four-Legged Minaret Mosque by recent clashes between Turkish security forces and Kurdistan Workers' Party militants.

Elci was a lead attorney in many cases dealing with Kurdish issues, including the deaths of 35 civilians in a 2011 airstrike in Uludere.

The semi-official Anadolu Agency reported that Elci was killed during clashes that broke out after "terrorists" from the Kurdistan Workers' Party, or PKK, fired shots near the minaret. The Diyarbakir Governorate said in a statement that security forces were attacked. Two police officers were killed and one wounded, and the governorate declared a curfew from 1 p.m. onward.

The Sur district and many predominantly Kurdish provinces have seen renewed conflict between Turkish security forces and the PKK. The 30-year war between Turkey and the PKK, which is considered a terrorist group by the United States, has claimed an estimated 40,000 lives. A two-year cease-fire ended in July.

In footage from the Dogan News Agency, gunshots are heard, and plainclothes police officers respond with gunfire. Elci and journalists stand behind police. Later, an armored vehicle arrives, and journalists try to follow it away. The gunshots intensify and the journalists begin to run. Another shot zooms in on a body on the ground, and it becomes clear that it is Elci, lying face-down.

Anadolu reported that Interior Minister Efkan Ala appointed four investigators, saying, "this attack is against our nation's unity."

Turkish President Recep Tayyip Erdogan condemned the attack. "This incident shows that Turkey's fight against terror is right," he said, adding, "Our struggle will continue till the end. We will not stop. We will not be tired. We will continue to be decisive in our fight against terrorism."

Prime Minister Ahmet Davutoglu said a police officer was killed when gunmen opened fire from a car about 100 meters from where Elci was shot.

He pointed to two possible timelines: "This might be an assassination against Tahir Elci," or "the second possibility is after the terror incident which took place 100 meters away, police were trying to protect the crowd, and there were two fires coming from two different sides, and Tahir Elci may have been killed in the crossfire. If this was the case, the ballistic report will say this."

Either way, Davutoglu said, the truth will come to light.

Reactions to Elci's death

The Diyarbakir Bar Association tweeted that "our president of the association, lawyer Tahir Elci was murdered by an assassination."

The HDP, or Peoples' Democratic Party, an opposition party with Kurdish roots, also said in a statement that Elci's death was an assassination and blamed the AKP, the ruling Justice and Development Party. "This planned assassination targeted law and justice through Tahir Elci. ... Tahir Elci was targeted by the AKP rule and its media and a lynching campaign was launched against him."

On October 19, an Istanbul court issued a warrant for Elci on charges of "propaganda for a terror organization" after the lawyer said on a CNN Turk program, "PKK is not a terrorist organization. ... Although some of its actions have the nature of terror, the PKK is an armed political movement."

He was released by the court on the condition that he not leave the country.

British Ambassador to Turkey Richard Moore tweeted, "Shocked and depressed by the murder of my friend Tahir Elci. A good and brave man cut down. A human rights defender over many decades."

The U.S. Embassy in Turkey tweeted, "We are shocked by the tragic death of Tahir Elci - a courageous defender of human rights."

The HDP called on "Turkey's democratic and peaceful powers, its citizens with conscience, professional associations and civil society organizations, political parties to raise their voices and show their democratic reactions."

Protesters in Istanbul who gathered in memory of Elci were dispersed by riot police.

Elci's funeral will take place Sunday morning in Diyarbakir.

Clashes at the crime scene

Investigation units, lawyers and security personnel were sent to inspect the crime scene. According to the Turkish Interior Ministry, the security officers were attacked by long-range weapons and by a bomb, which injured four officers in an armored vehicle.

"The crime scene was consciously damaged by this armed assault of terrorist elements who wanted to prevent the shedding of light on the event," said the ministry.

The committee could not conduct its inspection and clashes continued between the security officers and attackers.