David Cameron is expected to signal that the UK is ready to provide additional assistance in the fight against gangs smuggling migrants into Europe from Turkey.
The Prime Minister is expected to use a European Council summit in Brussels to voice strong support for proposals for Nato to monitor people-smugglers in the Aegean Sea, where thousands of people - many of them refugees from the Syrian civil war - have made the perilous crossing to Greece.
He will tell fellow leaders that the UK is ready to look at the redeployment of a Border Force cutter already in the region to take part in operations by the EU's Frontex external border agency, as well as the possible provision of a second cutter with maritime helicopter capability.
Britain is also considering sending additional liaison officers from the National Crime Agency to work with Turkish coastguards on tackling the smugglers, he is expected to say.
A meeting of Nato defence ministers last week agreed to develop proposals for action to increase reconnaissance, monitoring and surveillance of illegal crossings in the Aegean. A final plan is expected to be drawn up at an upcoming meeting of the North Atlantic Council.
Secretary General Jens Stoltenberg said at the time that the mission was "not about stopping or pushing back refugee boats", but about contributing "critical information and surveillance to help counter human trafficking and criminal networks".
He said that three warships from Nato Standing Maritime Group 2, under German command, were being moved immediately to the Aegean to help end Europe's gravest migrant crisis since the Second World War.
Arrivals in Greece have remained at around 2,000 a day even during the winter months, and more than 60,000 migrants are believed to have made the crossing from Turkey in January alone.
The International Organisation for Migration said 409 people have died so far this year trying to cross to Europe by sea, and nearly 10 times as many migrants crossed in the first six weeks of 2016 as in the same period last year. Most come from Turkey to Greece and then try to head north through Europe to more prosperous countries such as Germany and Sweden.