Ukrainian President Petro Poroshenko on Wednesday ordered the government to provide security to the head of the Ukrayinska Pravda newspaper after one of its journalists was killed by a car bomb in central Kiev.
"The president has held a meeting with security forces and instructed them to guard Olena Prytula," the president's spokesman, Svyatoslav Tsegolko, wrote on Twitter.
Prominent Belarus-born journalist Pavel Sheremet was killed while he was driving Prytula's car earlier in the day, Ukrayinska Pravda reported, adding that Prytula was not in the vehicle.
The homemade bomb had a power equivalent to 400 to 600 grams of TNT, the Ukrainian Interior Ministry said in a statement.
The explosion occurred outside a McDonald's restaurant at around 7:30 am (0430 GMT), state news agency Ukrinform reported.
The Organization for Security and Cooperation in Europe (OSCE), which has been independently monitoring the conflict between the Ukrainian military and pro-Russian separatists in eastern Ukraine for the past two years, condemned Sheremet's murder and called for a swift investigation.
"This morning's gruesome incident reminds us all that the safety situation for journalists in Ukraine must be addressed effectively and timely," OSCE media freedom representative Dunja Mijatovic said in a statement.
Reporters Without Borders said it was "deeply shocked" by the killing, adding that it was not yet clear if Sheremet had been the intended target since he was driving Prytula's car.
The organisation noted that Ukraine ranked 107 out 180 countries listed in its most recent World Press Freedom Index.
Sheremet, 44, wrote for the Ukrayinska Pravda newspaper and hosted a show on Radio Vesti. He had been living in Ukraine for about five years.
Sheremet had previously been a television presenter in his native Belarus, but a conflict with the ruling regime saw him receive a suspended sentence and he fled the country, Ukrayinska Pravda reported.
The newspaper's founder, Georgia-born investigative journalist Georgiy Gongadze, was abducted and murdered in 2000, and three former police officers were convicted for the crime eight years later. Gongadze's supporters accused the country's leadership of complicity in the killing.