British ambassador Julian Braithwaite told the council his country was "gravely concerned about the deteriorating human rights situation in Saudi Arabia", pointing to women's rights, mass arrests of rights defenders and extensive use of the death penalty.
"But most concerning is the murder of Jamal Khashoggi," he said, urging Saudi Arabia to "ensure comprehensive and transparent investigations into the murder" and to make sure "those responsible are held to account, and that measures are put in place to prevent any possibility of recurrence".
The US representative, Mark Cassayre, meanwhile said his country strongly condemned "this premeditated killing".
"A thorough, conclusive and transparent investigation carried out in accordance with due process with results made public is essential," he insisted.
The Saudi delegation, meanwhile, barely mentioned the case, choosing instead to highlight the "progress made towards the protection and promotion of human rights", including reforms that among other things have allowed women to drive in the ultra-conservative country.
But the delegation chief and head of the Saudi Human Rights Commission, Bandar Al Aiban, did touch on the case briefly, stressing at the end of the review that "our country is committed to carry out a fair investigation".
"All persons involved in that crime will be prosecuted," he said, stressing that "the investigation is continuing in line with our domestic laws".
Diplomats urged Saudi Arabia on Monday to take concrete steps to promote freedom of expression and protect human rights defenders and journalists.
The review also focused heavily on the use of the death penalty in the country, especially for alleged crimes committed when the perpetrator was under the age of 18.
The kingdom has one of the world's highest rates of execution, with suspects convicted of terrorism, homicide, rape, armed robbery and drug trafficking facing the death penalty. Many countries urged Saudi Arabia to introduce a moratorium on the death penalty or to abolish it altogether, and to explicitly ban its use for juvenile offenders.
Women's rights were also high on the agenda. While many countries hailed some progress in this area, including the fact that the country now permits women to drive, they warned that much more reform was needed.
The country especially faced criticism over its male guardianship system that allows men to exercise arbitrary authority to make decisions on behalf of their female relatives. Saudi Arabia's role in Yemen's brutal civil war also faced criticism, with a number of countries urging it to halt the devastating bombing campaign there.
The Saudi delegation, meanwhile, highlighted that it has provided more than $11bn in aid to Yemen since it and its allies intervened in the war in 2015 to bolster Yemeni President Abedrabbo Mansour Hadi after Iran-backed Houthi rebels took over the capital Sanaa.
According to the UN, more than 10,000 people have been killed in the conflict, which has also created the world's biggest humanitarian crisis and left millions of people on the brink of famine.
