More than 1,400 migrants landed on the Italian island of Lampedusa on Sunday.
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.
Sunday’s sudden surge has led populist politician Matteo Salvini to demand a meeting with the caretaker prime minister, Mario Draghi.
“With millions of Italians in difficulty, we cannot think of thousands of illegal immigrants,” he said.
Sunday’s sudden surge has led populist politician Matteo Salvini to demand a meeting with the caretaker prime minister, Mario Draghi.
“With millions of Italians in difficulty, we cannot think of thousands of illegal immigrants,” he said.
All migrants have been moved to the so-called “hot spot”, the island migrant centre.