The world’s largest container shipping company and the United Nations Secretary-General are appealing to governments to resolve a labor crisis that has stranded 400,000 seafarers on boats, according to a new estimate from the International Chamber of Shipping.

“I am worried that in respect of crew changes, little is going to change in most nations without action being taken at the very highest political level. We need actions now, immediate and real, from governments and national authorities,” Henriette Hallberg Thygesen, Chief Executive Officer of Fleet and Strategic Brands at A.P. Moller-Maersk A/S, said in a UN General Assembly meeting to discuss the ship workers long overdue for relief.

As the COVID-19 pandemic drags on and the number of seafarers stuck at sea climbs, calls to resolve the crisis are getting louder. At the United Nations meeting, officials expressed concerns that seafarers are being forced to work against their will and that the global supply chain is at risk.

More than 120 countries or territories have stopped or limited access for ships to conduct seafarer changes in a bid to prevent the spread of COVID-19 that has killed almost one million people across the globe.

While many shipping lines have managed piecemeal crew changes, the backlog of crew swaps has far outpaced relief efforts.