The European Union has signed an additional €25-million in funding to expand migration cooperation into eastern Libya, according to a letter from European Commission President Ursula von der Leyen to EU leaders seen by Reuters.

The funding will support border management, search-and-rescue and anti-smuggling activities in eastern Libya. It is a further sign of deepening EU engagement with the region controlled by military commander Khalifa Haftar as Brussels seeks to curb irregular migration across the Mediterranean.

Libya, where control is split between rival western and eastern administrations, has been a major transit route for migrants attempting the dangerous sea crossing to Europe since the 2011 NATO-backed uprising that toppled Muammar Gaddafi.

The EU and its member states have long supported and trained the Libyan coastguard, which intercepts migrants at sea. While the EU formally recognises only the Tripoli-based government, it has stepped up contacts with authorities in eastern Libya since last year as migrant departures from areas controlled by Haftar in eastern Libya have risen.

The move follows the July announcement by the EU that it would establish a Maritime Rescue Coordination Centre in the eastern Libyan city of Benghazi, further expanding cooperation with authorities in the east.

"Libya remains the top country of departure for illegal crossings to the EU," von der Leyen wrote, describing an upcoming EU-Libya meeting as a way to keep cooperation going.

She said the EU and the International Organization for Migration were supporting voluntary returns from Libya to countries of origin.

"We are equally focused on reducing the number of migrants arriving to Libya with the sole intention to cross illegally into the EU," she added.