The government will give at least £450m this year to alleviate the suffering of victims of the on-going Syrian civil war, she said at a Brussels conference on supporting the Western Asian country and the region.
The money will also provide support for Syrian refugees sheltering in neighbouring countries.
“Today’s pledge of UK aid support will help keep medical facilities open in the face of relentless attacks, so doctors and nurses can save the lives of innocent Syrians, as well as helping the millions of Syrian refugees sheltering in neighbouring countries,” Mordaunt said.
“But today can’t only be about pledges of money and we cannot allow anyone to turn their backs on the global rules and standards that keep us all safe.”
It is estimated that at least 478 health facilities have been attacked or destroyed in Syria, and at least 830 health workers have been killed since the conflict began in 2011.
“We’re calling for an immediate ceasefire and safe access so that brave aid workers and medical staff can do their jobs without fear of attack.
“This year, we must go beyond commitments. We must see concrete actions, which lead to greater protection for civilians and aid workers and work together to put Syria on a path towards peace,” Mordaunt said.
Last year the UK supported more than 175 health facilities, DfID said. The secretary of state has committed to provide at least £450m for Syria and the region this year, and £300m in 2019.
This brings the total amount that the UK has committed in humanitarian funding to the Syria region to £2.71bn.
The EU is the biggest donor to the Syrian crisis, contributing around €10bn since the war started.
The conference, which comprised more than 85 countries and NGOs, aims to raise billions of euros in aid to the region.
International donors pledged around €9bn last year.