Deadly Istanbul suicide attack blamed on IS

At least 10 foreign tourists have been killed and 15 other people wounded in a blast in the historic centre of Istanbul blamed on the Islamic State (IS) group.

Germany said at least eight of its nationals had been killed in the blast in the Sultanahmet district, while a Turkish official put the total number of Germans killed at nine.

German Chancellor Angela Merkel expressed “solidarity” with Turkey and added that Berlin would put up a determined fight against terror.

"We feel a sense of solidarity with Turkey," she said, adding that those who carry out such attacks, be it in Paris, or Copenhagen or Istanbul, have the same target - "our free life and free society".

Peru also confirmed one of its nationals had died in the attack, the foreign ministry in Lima said. Turkish media reports said German and Peruvian tourists were also among the wounded. 

Police sources named the attacker as Nabil Fadli, a 28-year-old Syrian born in Saudi Arabia, described by Turkish Prime Minister Ahmet Davutoglu as a member of IS.

"We have determined that the perpetrator of the attack is a foreigner who is a member of Daesh," Davutoglu said in Ankara, using an Arabic acronym for IS.

The blast happened at about 10:20am local time with force enough to be heard across the centre of the city, witnesses told the AFP news agency.

"The explosion was so loud, the ground shook. There was a very heavy smell that burned my nose," a German tourist named Caroline told the AFP news agency.

Turkish President Recep Tayyip Erdogan called for "unity and solidarity as a nation," reiterated Turkey's committment to fighting "terrorism" and condemned criticism of his government's policies from foreign sources.

UN Secretary-General Ban Ki-moon on Tuesday condemned the suicide bomb attack, calling it a "despicable crime" and said the perpetrators must face justice.

German tourism giant TUI said that customers who had booked trips to Istanbul could switch destination without penalties. The operator said customers can also opt to postpone their trip to Istanbul without penalties for the next six days.

Germans are by far the most frequent foreign visitors to Turkey, with 258,613 arriving in November 2015, accounting for 15 percent of all arrivals.

Some 5.4 million Germans arrived in Turkey between January and November last year.

Turkey has been on alert since 103 people were killed on 10 October when two suicide bombers attacked a crowd of peace activists in the capital Ankara, the bloodiest strike in the country's modern history.

That operation was blamed on IS, as were two other attacks in the country's Kurdish-dominated southeast earlier in the year.

Turkish authorities have in recent weeks arrested several suspected IS members, with officials saying they were planning attacks in Istanbul.

But Turkey is also waging a campaign on the outlawed Kurdistan Workers Party (PKK) which has staged dozens of attacks against members of the security forces in the southeast of the country. The military campaign in the Kurdish-majority areas has seen more than 600 PKK militants and over 150 civilians killed, according to human rights groups.

A PKK splinter group, the Kurdistan Freedom Falcons (TAK), claimed a mortar attack on Istanbul's second international airport on 23 December which killed a female cleaner and damaged several planes.

Meanwhile, the banned ultra-left Revolutionary People's Liberation Party–Front (DHKP-C) has also staged a string of small-scale attacks in Istanbul over the last months.

However, attacks by Kurdish and leftist groups have overwhelmingly targeted government buildings and security and state officials rather than civilians, while those same groups have been the primary focus of attacks by IS.