LONDON — European leaders meeting at an emergency summit Thursday in Brussels agreed to sharply expand maritime patrols in the Mediterranean amid a growing and increasingly deadly exodus of migrants seeking to reach the continent.

But the move fell far short of the measures that experts and human rights advocates say are necessary to confront the crisis. Absent more dramatic action, it seemed certain to fuel even more debate over whether European officials are putting politics over the welfare of some of the world’s most vulnerable people.

Despite intense pressure to restore the search-and-rescue mission that was canceled last fall, Europe’s leaders settled instead on tripling support for the current mission, which is focused on border security.

European officials also agreed to examine ways to crack down on the people-smugglers operating off North Africa — perhaps including by destroying their boats — and to speed the deportation of those who make it to Europe but don’t quality for asylum.

“Saving the lives of innocent people is the number one priority for us. But saving lives is not just about rescuing people at sea,” Donald Tusk, president of the European Council, said at a news conference after Thursday’s gathering in Brussels. “It is also about stopping the smugglers and addressing irregular immigration.”

Thursday’s summit came four days after the deadliest incident for migrants in the Mediterranean ever recorded, with more than 800 people believed to have drowned when a boat capsized off the Libyan coast.

Migrants have embarked on perilous and clandestine journeys to Europe for decades, sailing across the Mediterranean and traveling over land routes such as the mined border between Turkey and Greece. But a recent increase in numbers has alarmed European authorities as instability and violence — and the rising influence of the Islamic State — spreads across the Middle East and parts of Africa.

In an indication of the vast scale of the problem, more than 1,200 migrants have come ashore in Italy or were rescued at sea since Wednesday.

Refugee advocates say Europe’s approach, which is geared toward controlling borders and stopping smugglers, has been misplaced and ignores an unfolding humanitarian disaster.

“The European Union response needs to go beyond the present minimalist approach ... which focuses primarily on stemming the arrival of migrants and refugees on its shores,” the International Organization for Migration and the U.N. High Commissioner for Refugees said Thursday in a joint statement. “As a paramount principle, the safety, protection needs, and human rights of all migrants and refugees should be at the forefront of the EU response.”

The statement called for Europe to restore a search-and-rescue mission “without delay.”

Hours later, European leaders ignored that plea, choosing to expand the current border security effort rather than restore a search-and-rescue mission that ended in November.

The canceled Italian operation, known as Mare Nostrum, involved patrols seeking vessels in distress and sailing close to the North African coast. It was lauded for saving more than 100,000 lives. But it ended when other European countries refused to fund it amid accusations that it was drawing more migrants into the Mediterranean in hopes of being rescued and taken to Italy.

Its replacement, known as Operation Triton, patrols only within 30 nautical miles of the Italian coast and has no explicit rescue mandate.

First Published: April 24, 2015, 4:00 a.m.