The United Kingdom said on Friday it would pay $576 million over the next three years as part of a deal with France to combat illegal immigration across the English Channel.

The deal was announced during a joint summit between British Prime Minister Rishi Sunak and his French counterpart Emmanuel Macron in Paris on Friday.

The money will finance a new detention center for migrants in France and the deployment of 500 French security and support agents “to enable the fastest detection of attempted crossings” by small boats, a joint statement from the two countries said.

Friday’s meeting saw the two leaders stress their countries’ deep ties, following several years of tensions over post-Brexit negotiations, fishing rights, a submarine deal with Australia and immigration.

“The level of ambition of this plan is exactly what we need,” Macron said, adding, “this is not an agreement between UK and France but between UK and EU.”

Sunak, who faces criticism from human rights group for his moves to block cross-channel immigration with a new law criticized as racist, illegal and unworkable, said the UK “will always comply with our international treaty obligations.”

The UK has seen an increase in the number of illegal migrants who pay human trafficking gangs to smuggle them into Britain in small, non-seaworthy boats. Many of these boats have sunk, and people have died.

The 19-page joint statement from the Elysee Palace focused on the potential for greater defense cooperation between the two nuclear powers, from the deployment of fighter jets on each other’s aircraft carriers, to the joint production of future cruise missiles.

On Ukraine, the leaders promised closer cooperation, especially concerning the provision of equipment and munitions to Kyiv.

They also pledged support for the training of Ukrainian marines in the UK, while offering to pursue “security guarantees” with Ukraine “that will help [Kyiv] to defend itself long-term and to block potential future attacks,” the joint statement said.