At least 300 migrants are missing from three boats bound for Spain from Senegal, a Spanish aid organization said on Monday.

Helena Malino Carson, coordinator of the Walking Borders organization (Cominando Fronteras), said that on June 23, about 100 people left the town of Mbor and the third left the town of Kawondin in the south in four days. Later, with about 200 people.

“The most important thing is to find these people. Many are missing at sea. This is not normal. We need more planes to search for them,” he told The Associated Press.

It also stated that communication with the boats had been lost since their departure.

Neither Spanish nor Senegalese officials immediately responded to requests for comment.

The Atlantic crossing is one of the world’s most dangerous migration routes, with nearly 800 people dead or missing in the first half of the year, according to a Spanish body.

The Canary Islands have become a major destination for those seeking to reach Spain in recent years, with more than 23,000 migrants expected to arrive in 2020, according to the Spanish Interior Ministry.

In the first six months of this year, more than 7,000 migrants and refugees have arrived in the Canary Islands.

The Spanish relief agency said the boats were leaving mainly from Morocco, Western Sahara and Mauritania, and to a lesser extent from Senegal. Since June, at least 19 boats from Senegal have arrived in the Canary Islands, he said.

Struggling economies, unemployment, violent extremism, political unrest and the impact of climate change are pushing migrants to risk their lives on overcrowded boats to reach the Canary Islands.