Global condemnation followed Tuesday’s deadly terror attack on Istanbul’s Sultanahmet district with nations warning citizens to be wary of security threats in Turkey.

British Prime Minister DavidCameron telephoned President Recep Tayyip Erdogan Tuesday evening to express his condolences.

“They agreed on the importance of remaining resolute in fighting terrorism, and President Erdogan updated the prime minister on the investigation. The Prime Minister offered the U.K.’s support in establishing who was responsible for the attack,” a Downing Street spokesperson said.

The two leaders also discussed the upcoming London Syria Conference and agreed to work closely together to ensure its success.

Earlier Tuesday, Cameron told a House of Commons committee that Turkey was clearly stepping up its efforts in combatting Daesh. “If you look at for instance the work they’re doing along the Turkish border, the interdiction of oil supplies and oil smuggling, [and] the work they’re doing with partner intelligence services across Europe, including Britain. I would say they’re stepping up the work they’re doing to counter Daesh and we need to encourage that as much as we can,” Cameron said.

United Nations Secretary-General Ban Ki-moon also condemned the attack through his official spokesman. “[Ban] expects the perpetrators of this attack to be swiftly brought to justice,” Stephane Dujarric told reporters in New York.

“He sends his heartfelt condolences to the families of the victims, as well as to the people and the governments of Turkey and Germany and other foreign citizens impacted by the bombing. He wishes those injured a speedy recovery,” Dujarric added.

In Washington, the U.S. strongly condemned the attack.

“This heinous attack occurred in Istanbul’s historic heart, and struck Turks and foreign tourists alike,” National Security Council spokesman Ned Price said in a statement. “We stand together with Turkey, a NATO ally, a strong partner, and a valued member of the Counter-ISIL coalition, in the face of this attack and pledge our ongoing cooperation and support in the fight against terrorism.”

n Chancellor Angela Merkel called on the international community to be resolute in the fight against terrorism.

“International terrorism has once again showed itself, with its horrible and inhuman face,” Merkel told a news conference in Berlin.

The German Foreign Ministry, which has formed a crisis committee to handle the incident, warned its citizens to avoid crowds and tourist sites.

The suicide bomb attack in Istanbul on Tuesday morning killed 10 people, officials said. Turkish Prime Minister Ahmet Davutoglu said the suicide bomber was a foreigner who is a member of Daesh and that all of the victims in the attack were foreigners.

“This attack also shows us the necessity to confront terrorism in a resolute way,” Merkel said, adding that the government was in close contact with Turkey.

“My thoughts are with the families of the victims, with those injured and we will do everything to organize help as soon as possible, in cooperation with Turkey,” she said.

Despite strained ties between the two countries, Russian Foreign Ministry too wrote a message of condolence on its official website over the Istanbul’s attack; however the message was tied with condemnation of a separate attack in Baghdad on Monday.

Russia said in the statement that such “cynical attacks” were unjustifiable that demonstrated the ruthlessness and inhumanity of international terrorism. It also highlighted the need for the international community to unite against terrorism.

French Foreign Minister Laurent Fabius said in a statement that he condemned “in the strongest terms” the attack and expressed “the full solidarity of France to the Turkish people and authorities of the country hit hard again”.

The French Foreign Ministry has set up a crisis unit in Paris and Istanbul.

“Terrorism has once again struck one of our member states today. I deplore and strongly condemn the bomb attack in Istanbul. My thoughts are with the families and loved ones of the victims,” Anne Brasseur, president of the Parliamentary Assembly of the Council of Europe (PACE), said.

“I have expressed my condolences and support to the people of Turkey in a letter to the speaker of the Turkish parliament. Turkey can count on our support in combating terrorism and violent extremism. It is the duty of all democratic political forces to stand up against radicalization and the hatred that fuel violent extremism and terrorism,” Brasseur said.

Britain advised its citizens in Istanbul to follow directions of police and local officials.

“Following this morning’s explosion in the Sultanahmet area of Istanbul we are in touch with the Turkish authorities urgently seeking further information,” a spokesman of the Foreign Office in London said. “Our sympathies are with the victims and anyone affected by this attack.”

John Bass, the U.S. ambassador to Turkey, tweeted: “Closely following reports of an explosion in Sultanahmet. Our thoughts are with those affected”.

French Prime Minister Manuel Valls said countries attacked by terrorism should stand together. The November terror attacks in Paris killed 130.

Speaking after a party meeting at the National Assembly, Valls added: “France, Turkey, all countries that are attacked by terrorism need solidarity and [to] implement all necessary means to fight against the terrorist threat”.

He said he had no information on the presence of French nationals among the victims.

Paris Mayor Anne Hidalgo tweeted: “On behalf of the Parisians, my full support to the families and relatives of victims of the attack that occurred in Istanbul”.

EU President Donald Tusk tweeted: “I condemn the brutal terrorist attack in Istanbul today. My thoughts are with the victims.” (Anadolu Agency)

[adrotate banner=”67″]