The UN Security Council on Friday adopted a resolution to authorize the European Union and individual countries to seize migrant-smuggling vessels on the high seas off Libya.

"People cannot profit from this evil trade with impunity," British Ambassador Matthew Rycroft said, calling the crisis one of the greatest challenges of this generation.

The resolution, negotiated off and on for months, is under Chapter 7 of the UN Charter, which means it can be militarily enforced. African members of the 15-member council had expressed concern about that.

The resolution also authorizes the European Union and individual nations to board vessels "with a view to saving the threatened lives of migrants or of victims of human trafficking."

The International Organization for Migration says 2,987 migrants have died so far in 2015 in the Mediterranean Sea crossing.

The resolution authorizes the search and seizure operation for one year. It says migrants "should be treated with humanity and dignity."

Council diplomats have said migrants on vessels that are searched and seized would be taken to Europe.

The resolution underscores that the intention is not to prevent individuals from exercising their human rights or prevent them from seeking protection.

Venezuela was the only council member that didn't approve the resolution, instead abstaining and saying the crisis requires a broader approach beyond a military one. Rycroft called the abstention "disappointing" but acknowledged that the military approach is a "small part" of what's needed.

The EU initially wanted a naval operation in Libyan territorial waters and along its coast, but Libya objected. Its approval is needed for such an operation, but the North African country remains divided between two rival governments, which the UN is trying to lead into a final peace deal.

Smugglers have exploited the chaos in the country to launch often flimsy boats full of migrants and refugees toward Europe.

The UN envoy for Libya late Thursday proposed a national unity government after months of difficult talks. Rycroft urged the rival governments to "get with the program" and support it.

Moving to the next phase of the EU operation, intercepting migrant-smuggling boats in Libyan waters, will require "clear consent" from Libya and another council resolution, Rycroft said. He said there was no proposal yet to pursue that.

The original draft of the resolution approved Friday would have authorized the destruction of the vessels, but the resolution states that any action on disposal of a seized vessel must be taken in accordance with international law "with due consideration of the interests of any third parties who have acted in good faith."