* Rescues of boat migrants still increasing
* Hundreds of thousands already in Libya
* Some 1,000 die at sea in 2017, including 150 children
By Steve Scherer
ROME, April 21 (Reuters) - The number of migrants crossing Niger to reach Libya has declined, the International Organisation for Migration (IOM) said on Friday, after Europe pledged Niger money to help it fight people-smuggling.
The IOM monitors trucks carrying migrants at a desert crossroads in eastern Niger commonly used to reach Libya, where more than half a million have set out on flimsy boats for Europe in the past three years. Thousands have died in the crosssing.
The number of migrants observed at the transit point has fallen off significantly since September 2016, the IOM says.
Some 292,000 passed through the Niger town of Seguedine between February and December last year, while 8,700 came through in the first two months of this year.
Numbers in Agadez, where smugglers gather migrants for the dangerous Sahara crossing, also appear to have declined, IOM Niger mission chief Giuseppe Loprete told Reuters by telephone.
"The flows are not as high as last year. There's no comparison," Loprete said. "The government is blocking and arresting traffickers and confiscating trucks."
Last year, German Chancellor Angela Merkel promised 77 million euros to combat people-smuggling in Niger, one of the world's poorest countries, and the EU offered 610 million euros in aid.
This month Italy pledged 50 million euros ($54 million) to Niger's President Mahamadou Issoufou, saying it would be handed out in tranches and depended on Niger's control of its borders.
Federico Soda, the IOM's Rome-based director of coordination, cautioned that the declining flow from Niger did not mean fewer people will be sent out to sea this summer because hundreds of thousands of migrants are already in Libya.
European funds have been used to set up five centres in Niger that are managed by IOM, where migrants are fed, housed and offered a free trip home.
Some 5,000 were returned to their countries of origin from Niger last year, while 1,500 have gone back this year. From Libya, the IOM has flown almost 2,000 migrants home this year.
The UN refugee agency said in Geneva on Friday there were unconfirmed reports of 100 migrants missing in a shipwreck in recent days.
Italy says more than 36,000 have been rescued this year, up 44 percent on the same period of last year, while aid agencies estimate that up to 1,000 have died, including about 150 children.
(Additional reporting by Stephanie Nebehay in Geneva; editing by Andrew Roche)