By David Dolan
ISTANBUL (Reuters) - Iran's Foreign Minister Mohammad Javad Zarif joined his Turkish hosts in Istanbul on Saturday in condemning a suicide bombing by suspected Kurdish militants in a main shopping district that killed five people.
Zarif, on a visit to bolster bilateral trade and discuss political differences over the war in neighboring Syria, said the bombing - which also injured 36 people - "displays the ugly face of terrorism".
Iran has been a strong strategic ally of Syrian President Bashar al-Assad since the start of the uprising against him, while Turkey has been one of his fiercest critics, supporting his opponents and giving refuge to rebel fighters.
While Ankara and Tehran remain divided over the conflict in Syria, Zarif and his Turkish counterpart Mevlut Cavusoglu said both sides wanted to mend a relationship that could help establishment of peace and stability in the Middle East.
Turkey's foreign ministry has said the aim of the talks during Zarif's visit will be "current regional and international developments" as well as relations between the two countries.
Zarif suggested business would be high on the agenda. "We are seeking the best possible level of economic cooperation with Turkey after the nuclear deal," he told reporters in Istanbul.
After the lifting of international sanctions this year following a deal with Western powers to curb its nuclear program, Iran has become the biggest economy to rejoin the global trading system since the Soviet Union broke up more than two decades ago.
Gains by moderate allies of pragmatist President Hassan Rouhani in Iran's last month crucial elections have raised hopes for boosting foreign investment in Iran, a country with 80 million people and some of the world's biggest oil and gas reserves.
"Iran and Turkey enjoy many commonalities ... The leaders of Iran and Turkey seriously want to further develop economic ties," Zarif told Iran's state news agency IRNA in Istanbul.
"We face common regional threats and of course have different views regarding some issues that should be resolved through dialogue and negotiations."
At a news conference after meeting Cavusoglu, Zarif said Syria's national unity and territorial integrity had to be respected.
"We strongly believe that as neighbors of Syria, Iran and Turkey can work together to bring peace to Syria. We are ready to help people in Syria to decide about their country's fate," Zarif said.
Hopes of a breakthrough at the Syria peace talks in Geneva remain slim despite a more than two-week-old "cessation of hostilities" and Russia's pulling out some of its forces.
Assad's government has ruled out the idea of a federal system in Syria after a Russian official said that could be a possible model.
Turkey, whose conflict with the Kurdish PKK has escalated in recent months, has ruled out the declaration of a federal region in Kurdish-controlled areas of northern Syria.
Cavusoglu said the Syrian Kurdish PYD party, which Turkey sees as an extension of the PKK, and the affiliated Syrian Kurdish YPG militia had "shown their real faces".
"They want to divide Syria. With Iran, we support the territorial integrity of Syria," he told the news conference.
Zarif is also due to meet with President Tayyip Erdogan, and Prime Minister Ahmet Davutoglu during his visit.
(Additional reporting by Tulay Karadeniz and Parisa Hafezi in Ankara; Writing by David Dolan and Parisa Hafezi; Editing by Tom Heneghan)