More than 1,000 migrants landed on the Italian island of Lampedusa in the space of a few hours on Sunday, according to local media reports.
One boat alone was carrying almost 400 men, women and children, Italian news agency Ansa said.
The island’s Mayor Toto Martello said he believed the rise in arrivals coincided with the good weather.
Lampedusa is one of the main arrival ports for people wanting to reach Europe.
More boats were spotted off the coast of nearby Malta, with charity Alarm Phone saying they needed assistance.
“One rescue operation could put a total of around 231 people out of danger of drowning,” it said.
Some 11,000 migrants have landed on the island since the start of the year.
That is up on last year’s figure of 4,105 for the same period.
However, it is still down on 2015 – the height of the migrant crisis.