Khalil Senosi, Associated Press
Kenyans wearing animal masks join demonstrators as they walk through the streets of Nairobi, Saturday, Oct. 3, 2015, participating in a Global March to support wildlife Elephants and Rhinos. Kenya is a leading wildlife safari destination that has been grappling with declining wildlife numbers, some thousands of people walked 10 kilometers in the capital Nairobi.

JOHANNESBURG — A vehicle carrying a rhino sculpture led anti-poaching marchers in Johannesburg on Saturday. Kenya's environment minister joined conservationists at a similar rally in Nairobi, the capital. In London, activists in elephant costumes demanded an end to the ivory trade.

The demonstrations were part of what organizers called a "global march" for rhinos and elephants, whose populations have been severely reduced by criminal networks that sell rhino horn and elephant ivory for high prices, particularly in parts of Asia. The loosely knit coalition of conservationists also planned events in the United States this weekend.

Organizers want governments to focus more on protecting wildlife, but acknowledge that major challenges such as poverty, state corruption and lax law enforcement facilitate poaching. South Africa is grappling with a record surge in rhino poaching, and poachers have slaughtered tens of thousands of elephants annually around Africa in recent years.

In September, President Barack Obama and Chinese President Xi Jinping of China agreed to implement nearly complete bans on the ivory trade.

"Why not a total ban?" said Dex Kotze, a march organizer in Johannesburg.

He noted that conservationists in South Africa are divided between those, including himself, who oppose proposals to allow a regulated trade in rhino horn, and those who say controlled trade could drive criminals out of poaching. South Africa is reviewing the issue.

The Johannesburg march was held in the Sandton area, where some motorists honked in appreciation.

Protester Annette Erasmus said she was disappointed that the rally had not been joined by representatives from South Africa's legal wildlife hunting industry, which says it helps preserve animal populations. Hunting in Africa has come under increased scrutiny since an American dentist killed a popular lion named Cecil in Zimbabwe in an allegedly illegal hunt.

"We need to get more people out here," Erasmus said.