In Brussels, local support group Samusocial is trying to help them and has set up a crisis centre for those tested positive with COVID-19.

"Ah yes hold on, I forgot to ask you for a little bottle of disinfectant," says Nelly, a 72-year-old homeless woman as she turns to Roberto, a social SAMU nurse looking for people to help with his colleague Edwige.

Wrapped up in a coat and huge scarf, Nelly has set up in a pedestrian tunnel under the tracks of one of the city's main railway stations, where she is sheltered from the rain but not the wind.

"We always try not to go where there are too many people, I avoid it," she explains. A way of living that she is following even more closely during the pandemic.

"There's less risk in being outside than in confined spaces," says Nelly, who does not like homeless shelters.

"I do everything on foot, I avoid approaching people, you do what you can to get by."

The order to stay at home except for essential trips, imposed by many countries including Belgium, is particularly challenging for the homeless, says Sebastien Roy, the head of Samusocial.

"It's not adapted to the kind of situation we look after -- night shelters and the homeless world," he told AFP.

Later on their round, Edwige and Roberto go to Marolles, a gritty district of the city known for its flea market, after getting a call about a man on crutches having difficulties.

"These people are alone, with no contact -- I think they are suffering more in the current situation than those of us who just have to stay at home," said Katia, the woman who alerted Samusocial to the man in trouble.

- Tensions -

Three men approach the Samusocial van -- regulars who ask for socks, warm clothes and food.

"Now we're at the level of survival," Edwige says.

"We see them getting hungrier and hungrier. It's okay for the moment but we only have tins of tuna left. They ask for water a lot but we haven't got any."

As for hygiene, the situation is "catastrophic", she says.

A lot of support groups that offered free showers have had to close -- because staff have been told to stay at home or because the people using them are old and seen as vulnerable.

Samusocial is recruiting to try to cope, in particular medical staff. It has set up a centre to receive homeless people suspected of having coronavirus and is asking for tests for everyone staying in shelters.

"Through our rounds, the feedback that we get, we see tensions are growing because people are seeing their system of resistance or resilience declining," Roy says.

"Less begging is possible, access to food is more difficult, a lot of day centres are closed and so the tension is palpable among homeless people and migrants in transit as well."

What is more, he said, police enforcing strict lockdown rules mean homeless people cannot even sit on street benches or rest in parks.

"All these factors make them feel more threatened and so under more tension than before," he says.