Turkey plans to bolster security along its border with Syria following a suspected suicide bombing in the town of Suruc which killed 30 people, most of them students.
The Turkish prime minister, Ahmet Davutoglu, announced the plans at a news conference on Monday after President Recep Tayyip Erdogan earlier condemned the attack as "an act of terror".
"Measures on our border with Syria will continue, and will be increased," Davutoglu said.
"But our citizens should consider that countries experiencing tension, instability and clashes in the region could turn out to affect Turkey's inner peace."
The Islamic State of Iraq and the Levant (ISIL) is suspected of the attack, which killed mostly students.
Protests blame government
Also on Monday, Turkish riot police fired tear gas and water cannon during a protest in Istanbul that blamed the government for not doing enough to prevent the bombing on the mostly Kurdish town.
Hundreds gathered near the city's central Taksim Square, and chanted slogans against Erdogan and the ruling AK party, including: "Murderer Islamic State, collaborator Erdogan and AKP", the Reuters news agency reported.
Turkey's Kurds have accused Ankara of failing to do more to stop ISIL.
The PKK Kurdish militant group said it held the government responsible for Monday's attack, saying Ankara had "supported and cultivated" ISIL against the Kurds in Syria.
Similar protests were also staged in Ankara and Diyarbakir.
Mostly students killed
The Suruc attack killed activists, mostly students, who were set to travel to Kobane, located about 10km away inside Syria, in an effort to rebuild the town.
Kobane has seen fierce fighting between Syrian Kurdish forces and ISIL in recent months.
The blast happened outside a cultural centre, where members of the Federation of Socialist Youth Associations (SGDF), the organiser of the event, were making a press statement.
|The moment and the aftermath of the attack were captured by cameras [EPA]
Footage on the Dogan News Agency website showed activists gathered under SGDF banner and chanting slogans just before the blast hit the group.
Other footage and social media photos showed dead bodies lying on the ground.
"We were planning to take 200 people to Kobane, but the governorship allowed 50 people to cross the border. The group was planning to leave in the [Monday] evening, but could not," Akdag, the witness, told Al Jazeera.
"This was an effort to do whatever we could to rebuild Kobane, from rehabilitation of children and social activities to help with the construction and health services. We were carrying toys and supplies there. I was going to perform a play."
Another blast hit Kobane moments after the Suruc attack.
Flow of refugees
Turkey's Western allies have been demanding tougher measures against ISIL, including tighter controls on its 822km-long border with Syria, where there is an ISIL presence.
According to the UN numbers, there are more than 1.8 million Syrian refugees in Turkey, including thousands in camps around Suruc, which makes monitoring a difficult task.
"Suruc is located just across the border from Kobane. Kobane is a very emotional place for Kurds as they fought ISIL at this particular town, standing their ground," Andrew Finkel, a foreign correspondent who has been based in Turkey for over 20 years, told Al Jazeera.
"The people attending the youth club, where the explosion happened, were volunteering their services for their brothers across the Syrian border. So this is an attack at the heart of the empathy Kurds in Turkey feel for their brothers."
Kobane witnessed fierce battles between Kurdish fighters controlling the town and ISIL until February. The town is still a target of suspected ISIL attacks.
Source: Al Jazeera and agencies