The comments from Haitian President Jovenel Moise add to the condemnation the anti-poverty charity has received since the Times revealed last week some Oxfam employees paid for sex while working in Haiti among people devastated by the 2010 quake.
The 48-year-old later tweeted: "All I can tell you about this bad revelation about Oxfam is that I am devastated".
Asked about Evans's allegations, Oxfam said her work had spurred the organisation into taking concrete steps to improve the way it deals with "safeguarding" issues.
Oxfam, which received €1.7 million ($2.1 million) in funding from the European Union for work in Haiti in 2011, is being accused of covering up the episode and failing to warn other aid agencies about the employees involved, which allowed them to get jobs among vulnerable people in other disaster areas.
United States futures sink as strong inflation data raises rate hike fears
USA stock-index futures turned firmly lower on Wednesday, after the January consumer-price index came in stronger than expected. Excluding the volatile food and energy components, the CPI shot up 0.3 percent, the largest increase since January 2017.
The Charity Commission has also opened a statutory inquiry into Oxfam, saying the organisation may not have "fully and frankly disclosed material details about the allegations at the time in 2011".
Oxfam has denied covering up the scandal, which triggered the resignation of its deputy chief executive on Monday.
There were reports on Wednesday that there had already been complaints about van Hauwermeiren when he worked for the British medical charity Merlin in Liberia.
The Charity Commission said it had contacted Save The Children to establish if it had records of Ms Miller's complaints.
Oxfam said that with 10,000 NGOs working in Haiti alone in 2011, "it was unfortunately not possible for Oxfam to ensure that those found guilty of sexual misconduct were not re-employed in the sector". On average there are 600 cancellations per month. "The case for the type of work done by Oxfam is too strong to allow it to be undermined by bad behaviour", he said.
Trump weighs tariffs, quotas on United States steel, aluminum imports
The Trump administration has imposed tariffs on solar panels, washing machines, lumber, paper, steel and many industrial products. He added that with the sheer volume of trade and integration between the USA and Chinese economies, some friction was natural.
Penny Mordaunt, the worldwide development secretary, said that she would meet the National Crime Agency (NCA) tomorrow after talks with charity bosses and regulators.
Ms Mordaunt is due to give a speech to representatives from global aid agencies and ministers from over 20 countries at the Agenda 2030 for Children: End Violence Solutions Summit.
At an event in Stockholm to find ways to end violence against children, she said: "No organisation is too big, or our work with them too complex, for me to hesitate to remove funding from them if we can not trust them to put the beneficiaries of aid first".
The official charity of the UK's Catholic bishops hired a former Oxfam worker who was involved in that charity's sex-with-earthquake victims scandal, which is just now coming to light.
In another blow to the Oxfam brand, prosecutors in Guatemala said that they had detained Juan Alberto Fuentes Knight, the chairman of Oxfam International.
Germany considers free public transportation in most polluted cities
The Federal Administrative Court in the eastern city of Leipzig is considering the legality of driving bans on February 22. If Vella is not satisfied with Germany's proposals, he has threatened to file a case with the European Court of Justice.