GENEVA (Reuters) – The number of people forced into modern forms of slavery by poverty and other crises has risen by a fifth in recent years to around 50 million on any given day, the UN International Labour Organization (ILO) said on Monday.

More than a half of those had been forced to work against their will and the rest forced into marriage, the ILO said.

Both came under its definition of modern slavery as they involved people who “cannot refuse or cannot leave because of threats, violence, deception, abuse of power or other forms of coercion,” it added.

The situation had been exacerbated by crises such as COVID-19, armed conflicts and climate change which had left more people in extreme poverty and forced more to migrate, the agency said.

“I think, by and large, that we simply relaxed our efforts. We’ve taken our eye off the ball when it comes to forced labour,” ILO Director-General Guy Ryder told Reuters, calling for improvements in recruitment practices and labor inspections.

He said trade measures, such as a ban on products and imports made with forced labor currently under review by the European Union, could also help.

Compared with the last count for the year 2016, the number of people in modern slavery has risen by around 9.3 million, the report said.

The ILO, which based its estimates partly on household surveys, found that more than half of all forced labor occurred in upper-middle income or high-income countries, with migrant workers more than three times as likely as locals to be affected.

The ILO report also pointed to concern about accusations of forced labor in parts of China.

It referred to a report released by the U.N.’s rights office on August 31 that said “serious human rights violations” had been committed in China and that the detention of Uyghurs and other Muslims in Xinjiang may constitute crimes against humanity.

China has vigorously denied the accusations and last month ratified two conventions against forced labor.