The US Federal Emergency Management Agency (FEMA) has reportedly suspended a number of staff who criticized the agency's direction under US President Donald Trump. The staff are said to have been among those who recently signed an open letter that castigated Trump officials over cuts and alleged interference, warning that another 'national catastrophe' akin to Hurricane Katrina was possible. More than 20 employees were told on Tuesday that they had been put on administrative leave, according to sources who spoke to the BBC's US partner, CBS News. Asked by the BBC for a comment, a FEMA spokesperson said the agency's obligation was to survivors of disasters, 'not to protecting broken systems.' The spokesperson also said: 'It is not surprising that some of the same bureaucrats who presided over decades of inefficiency are now objecting to reform.' 'Change is always hard. It is especially for those invested in the status quo, who have forgotten that their duty is to the American people not entrenched bureaucracy.' There has been renewed scrutiny of US disaster readiness after recent deadly flooding in Texas, and as a result of Trump actions during his second presidency. Trump set about drastically overhauling the disaster-management agency soon after returning to office in January, when he mooted the idea of 'maybe getting rid of FEMA' altogether. Reports suggest that hundreds of employees - representing about a third of FEMA's workforce - have left their jobs since the start of the year for various reasons. Of the 191 FEMA employees who signed Monday's open letter criticizing the agency's direction under Trump, the majority remained anonymous. The letter reflected on the 20th anniversary of Hurricane Katrina, pointing out that the storm had claimed more than 1,800 lives and had highlighted the need for competent American disaster-management leadership. It took the Trump administration to task for cuts to the agency's funding and workforce, the failure to appoint a permanent agency boss and other issues including the perceived 'censorship of climate science.' Addressing the Federal Emergency Management Agency Review Council, the letter made demands including a defense against 'interference' from the Department of Homeland Security (DHS) and an end to 'politically motivated firings.' The aim was to 'prevent not only another national catastrophe like Hurricane Katrina, but the effective dissolution of FEMA itself,' the document said. In response to the letter, a FEMA official defended the agency's work and reforms under Trump - saying it was committed to delivering for the American people and had previously been 'bogged down by red tape' and other inefficiencies. DHS is yet to respond. Scores of people died in the disaster - including 27 attendees of a girls' summer camp. Questioned by lawmakers about accusations that some rescue work had been delayed, FEMA's acting administrator described the response as a 'model' one. The row over the FEMA suspensions comes with the North Atlantic hurricane season under way and with expectations that the agency will be busier than usual because of warmer sea temperatures – made more likely by climate change.