The latest round of talks at the United Nations aimed at securing protections for marine life in international waters that cover half the planet ended without agreement Saturday.

The fifth round of discussions, which began two weeks ago, were designed to establish a UN Ocean Treaty that would set rules for protecting biodiversity in two-thirds of the world’s oceanic areas that lie outside territorial waters.

But UN members failed to agree on how to share benefits from marine life, establish protected areas, or to prevent human activity with life on the high seas.

“Although we did make excellent progress, we still do need a little bit more time to progress towards the finish line,” UN oceans ambassador Rena Lee said, according to Agence France-Presse.

Many hoped that the New York session, which began on 15 August, would ultimately produce an agreed treaty text on “the conservation and sustainable use of marine biodiversity beyond national jurisdiction”.

But environmental campaigners, who noted that discussions had been continuing on and off for 15 years, expressed disappointment and blamed wealthy countries, including the US, of being too slow to compromise.

Among the issues holding up the treaty is agreement on a process for creating protected areas as well as environmental impact assessments.

“While progress has been made, particularly on ocean sanctuaries, members of the High Ambition Coalition and countries like the USA have moved too slowly to find compromises, despite their commitments,” said Laura Meller of Greenpeace’s Protect the Oceans campaign.

Meller said that some groups, like the Pacific islands and the Caribbean group, had pushed to complete the agreement. But countries in the global north had only started working to reach compromises in the final days of negotiations, she said.

“Time has run out,” Meller added. “Further delay means ocean destruction. We are sad and disappointed. While countries continue to talk, the oceans and all those who rely on them will suffer.”

Greenpeace had warned Thursday that treaty talks were on the brink of failure because of the greed of countries in the High Ambition Coalition and others such as the US and Canada. At issue, the group said, was prioritizing hypothetical future profits from Marine Genetics Resources over protecting the oceans.

Meller also said that Russia had blocked negotiations, refusing to engage in the treaty process and in attempts at compromise with the European Union “on a wide range of issues”.

Monica Medina, the assistant US secretary of state, said her country remained committed to the goal of protecting at least 30% of the world’s oceans by 2030. “We cannot let the tides and currents push us back,” Medina said. “We must keep going.”

Unless the UN general assembly schedules a special emergency session to conclude negotiations, talks will not automatically resume until next year.

If the body fails to do so, Greenpeace warned that “it will be challenging to protect 30% of the world’s oceans by 2030 – the 30×30 target that scientists say is the minimum needed to give the oceans space to recover”.

The failure to reach an agreement comes after world leaders at the UN Ocean Conference in Lisbon in July vowed to do everything in their power to save the seas. But despite uplifting calls to action in the closing statement, no clear commitments emerged.

“While it’s disappointing that the treaty wasn’t finalized during the past two weeks of negotiations, we remain encouraged by the progress that was made,” said Liz Karan of the NGO Pew Charitable Trusts of the latest round of talks.

Agence France-Presse and the Associated Press contributed reporting.