Yemen suffered more airstrikes in the first half of this year than in the whole of 2016, increasing the number of civilian deaths and forcing more people to flee their homes, according to a report by international aid agencies.
The pace of clashes on the ground has also intensified this year, especially around Yemen's third largest city, Taiz, which is besieged by the Iran-aligned Houthis, said the report.
The number of airstrikes in the first six months of 2017 totalled 5,676, according to the report by the Protection Cluster in Yemen, which is led by the United Nations High Commission for Refugees (UNHCR), up from 3,936 for all 2016.
Average monthly clashes between the warring sides have increased by 56 per cent from last year, the figures also showed.
[We are concerned by] the increasing impact on the civilian population, particularly in terms of civilian casualties, fresh displacement and deteriorating conditions
said Shabia Mantoo, UNHCR spokesperson for Yemen.
Yemen's nearly 30-month-old civil war pits President Abd Rabbuh Mansour Hadi's Saudi-backed government, which controls south and eastern Yemen, against the Houthis, who control the more populated north and eastern parts of the country.
The conflict shows no sign of ending and UN-sponsored peace efforts remain deadlocked.
The report did not identify any party as being responsible for the airstrikes, but the Saudi-led coalition backing Hadi has controlled Yemeni airspace since the war began in March 2015.
US forces have also conducted airstrikes or raids using drones.
A coalition spokesman declined to comment on the report.
The United Nations has put the death toll since the war began in March 2015 at more than 10,000.
"[The figures are considered] to significantly undercount the true extent of the casualties, considering the diminished reporting capacity at health facilities and people's difficulties accessing healthcare," the OCHA said.
The number of displaced people stands at two million, while 946,000 people are internally displaced returnees, OCHA said.
"Ongoing hostilities in Yemen, compounded by cholera and widespread food insecurity, continue to increase the humanitarian needs of an already vulnerable population," said UNHCR's Mantoo.