The office of the United Nations' human rights office says deaths among civilians due to Yemen's conflict have been "steadily mounting" with more than 200 people killed and more than 500 wounded in four months, including 50 in one week.

The spokeswoman for the U.N. High Commissioner for Human Rights Ravina Shamdasain said on Friday that violence has been escalating across Yemen.

She noted that July and August witnessed the worst incidents with eight children killed in a July 5 rocket attack in the eastern city of Marib. On Aug. 7, 16 civilians were killed in airstrikes in the district of Nihm, east of the capital Sanaa.

Since March 2014, a Saudi-led military coalition has waged a campaign against Shiite rebels and allied forces who occupy the capital.