For the past 35 years, Nuri Sahin has sold carpets in the historic center of Istanbul. He can’t remember a time when business was so bad and fears that it will only get worse.

Just a smattering of tourists ventured to the plazas and cobbled streets near his shop on Wednesday, a day after a suicide bomber thought to be linked to the Islamic State killed at least 10 people after approaching a group of German tourists and detonating his vest. Meanwhile, Turkish authorities carried out raids across the country, arresting one person in connection with the attack, according to Turkish Interior Minister Efkan Ala.

Terrorist attacks are nothing new for Turkey, but Tuesday’s bloodshed marked a possible pivot point: the Islamic State apparently turning its focus toward the tourism sector in a country that draws about 40 million visitors a year.

The attack took place near three of Istanbul’s most famed tourist attractions: the Blue Mosque, the Ottoman-era Topkapi Palace and the Hagia Sophia, a former mosque and Christian basilica that’s now a museum.

“The tourists will be scared for a year,” said Sahin, 47. “This is the first time we’ve had anything like this in the heart of our tourism area.”

His colleague, Suleyman Bala, 33, witnessed the blast as he sat near the Obelisk of Theodosius, an ancient Egyptian monolith. The square was relatively quiet, he said, with just two tour groups: one of Germans, another of South Koreans. When the blast went off, he dropped to the ground.

“It was all around me, body parts, blood,” he said. “So many pieces of people and people running, people scared.”

Germany’s Foreign Ministry said on Wednesday that all 10 who died were German citizens. Previous reports had said a Peruvian was also killed.

Seventeen were injured, and 11 remain in the hospital. Turkish authorities have blamed the Islamic State for the attack, though the group has not asserted responsibility.

During a visit to Istanbul, Germany’s interior minister, Thomas de Maiziere, said there was no reason to think that the attack was directed specifically at Germans, who make up the largest group of visitors to the country.

The number of Russian tourists began to drop after Moscow advised its citizens not to visit amid worsening relations following Turkey’s downing of a Russian fighter jet in November.

With the bomb attack Tuesday, the Islamic State risks a harsher crackdown from Turkish authorities, who have been criticized for not doing enough to prevent the country from being used as a conduit for supplies and recruits. But the militants appear increasingly desperate to strike overseas as they lose territory in Iraq and Syria.

In a joint news conference with Maiziere, Ala said that a woman was detained late Tuesday in Istanbul in connection with the attack, but he gave no further details.

It was one of a series of raids in the wake of the attack against suspected Islamic State cells.

In the Mediterranean city of Antalya, three Russians were detained for allegedly providing logistical support to the militant group, the state-run Anadolu news agency reported. Six other suspected militants were arrested in raids in the province of Izmir on the Aegean coast.

The alleged bomber, a 28-year-old Syrian named Nabil Fadli, was not on any militant watch list but had registered and given fingerprints at an immigration office a week before the blast, Ala said. Quoting security sources, the Turkish newspaper Hurriyet Daily said that he had registered for asylum in Istanbul on Jan. 5 with four other men.

The pan-Arab daily newspaper al-Hayat reported that the man was born in Saudi Arabia but left at age 8 with his family.

The bombing took place just yards from the city’s Blue Mosque, whose nine domes and six minarets are one of the most recognizable features of the city’s skyline.

“It’s just very, very sad,” said Kate Burton, a 36-year-old Australian tourist, wiping away tears as she and her husband went to buy flowers to lay at the scene of the blast. “You get to know the locals, you really feel for them.”

She said they would not be deterred from visiting again. But Sahin had his doubts.

“I’ve never seen it like this in my life,” he said, adding that business was already down 70 to 80 percent. “We are scared now that the third world war is coming.”

Brian Murphy in Washington contributed to this report.