Human rights office says figure includes additional killings from earlier periods as well as deaths since last report in July 2013

The death toll from Syria's civil war has risen to more than 191,300 people, the United Nations has said.

The figures for March 2011 to April 2014 are the first to issued by the UN's human rights office since July 2013, when it documented more than 100,000 killed.

The UN's top human rights official, Navi Pillay, who oversees the Geneva-based office, said the figures are so much higher because they include additional killings from earlier periods, as well as deaths since the last report. The exact figure of confirmed deaths is 191,369, Pillay said.

"As the report explains, tragically it is probably an underestimate of the real total number of people killed during the first three years of this murderous conflict," she said.

Pillay, the UN high commissioner for human rights, criticised what she described as the world's "paralysis" over the fighting in Syria, which "has dropped off the international radar" in the face of so many other armed conflicts.

In January, her office said it had stopped updating the death toll, blaming a lack of access in Syria and its inability to verify source material. It was unclear why it has released new figures now.

The UN also would not endorse anyone else's count, including the widely quoted figures from the Britain-based Syrian Observatory for Human Rights, which has closely counted the deaths since Syria's crisis began in March 2011. On Thursday, the observatory said the number of deaths has reached 180,000.