Rishi Sunak has agreed to strengthen co-operation with the EU over illegal migration, Downing Street has said.
The PM met with European Commission President Ursula Von der Leyen and agreed a new arrangement between British agencies and Frontex, the European Border and Coast Guard Agency.
It comes as the Government desperately tries to get a grip on Channel crossings after pledging to bring them to an end.
The PM is set to meet the head of the European Court of Human Rights, Siofra O'Leary, in a desperate bid to get the deportation flights - branded a "gimmick" by critics - in the air.
But leaders at the Council of Europe meeting, where Mr Sunak will meet leaders, will not "have a big focus on migration", host country Iceland said.
A No10 spokesman said of the meeting with Ms Von der Leyen: "The Prime Minister and President Von der Leyen underlined that the UK and EU have a shared interest in tackling cross-border crime and people trafficking.
"They agreed to strengthen co-operation between the EU and UK on migration through developing a new working arrangement between UK agencies and Frontex, enabling us to work together on critical operational and strategic challenges including the situation in the Channel.
"UK and EU teams will now discuss the details and operationalisation of this new working arrangement."
He is set to tell European heads of state in Reykjavik that the international system for policing human trafficking is "not working".
And the PM is also set to call for reforms to rules that prevented the UK's first scheduled deportation flight taking asylum seekers to Rwanda.
But Iceland's foreign affairs minister Thordis Kolbrun Gylfadottir suggested these issues will not be top of the agenda at the gathering.
She told BBC Radio 4's World At One programme: "The biggest focus is of course Ukraine, and then other issues such as AI and environment and other things. So this summit doesn't have a big focus on migration in general.
"But I agree that that is an issue for Europe. And of course, that system has to develop with the challenges that we face."
Mr Sunak will hold talks with the president of the European Court of Human Rights (ECHR), Siofra O'Leary, over reforms to how Rule 39 works - the order that blocked the inaugural flight to Kigali last year.
Asked whether Iceland and other European nations will consider an overhaul of the rules, Ms Gylfadottir said: "I believe that there will be a discussion on it, but there will not be I think a real concrete outcome on reforming certain articles."
Immigration will also come up in the Prime Minister's bilateral meeting with European Commission president Ursula von der Leyen, Downing Street said.
His official spokesman told reporters: "I'm not going to pre-empt their discussion, but I imagine they will talk about Ukraine following president (Volodymyr) Zelensky's visit to other countries and to see the Prime Minister yesterday.
"And I would have thought they will talk about the challenge of illegal migration."
It comes as his Government scrambles to bring in new laws designed to stop asylum seekers crossing the English Channel in small boats.
The Illegal Migration Bill aims to send asylum seekers who arrive in Britain via unauthorised routes back home or to a third country such as Rwanda, as well as cutting the daily £5.5 million cost of housing migrants who make it to the UK.
No 10 said the Government "remains committed" to reducing net migration amid speculation it could pass the one million mark next year.
It follows reports that the Home Office has privately shared figures with No 10 suggesting more than 1.1 million foreign workers and students could legally arrive in Britain in 2024/25, just as the Tories face a general election test.
