UNITED NATIONS (Reuters) - The United Nations Security Council unanimously approved on Wednesday the deployment of up to 75 observers to Yemen’s port city of Hodeidah for six months to monitor a ceasefire and redeployment of forces by the warring parties.

After a week of U.N.-sponsored peace talks in Sweden last month, the Iranian-aligned Houthi group and Saudi-backed Yemen government forces reached a ceasefire deal on Hodeidah, the entry point for most of Yemen’s commercial goods and aid, and a lifeline for millions of Yemenis on the verge of starvation.

The 15-member Security Council last month authorized an advance monitoring team led by retired Dutch General Patrick Cammaert and asked U.N. Secretary-General Antonio Guterres to recommend a larger operation.

Guterres said up to 75 truce monitors would be needed and the Security Council adopted a British-drafted resolution on Wednesday to authorize that deployment. The operation will be known as the U.N. Mission to support the Hodeidah Agreement (UNMHA).

A military coalition led by neighboring Saudi Arabia intervened in Yemen in 2015 to back government forces. The U.N. and Western countries have criticized the coalition for killing a large number of civilians, including children.

The Gulf states accuse Iran of supplying arms to the Houthis, a charge Tehran and the group deny.

In a letter to the Security Council on Tuesday - seen by Reuters - Saudi Arabia, the United Arab Emirates and Yemen accused the Houthis of 573 violations of the ceasefire, leading to the death of 41 coalition forces and wounding of another 396.

“The coalition hopes that the deployment of an increased number of U.N. monitors will help to ensure greater compliance by the Houthis,” they wrote.

On Sunday, Houthi spokesman Mohammed Abdul-Salam criticized the United Nations handling of the redeployment of troops in Hodeidah. He wrote on Twitter that if the situation was not fixed “then it will be difficult to hold discussions on any other issues.”

However, Yemen’s warring sides started talks on Wednesday in Jordan over a deal to free thousands of prisoners as part of U.N.-led peace efforts, two U.N. sources said.

In Guterres’ Dec. 31 proposal to the council, seen by Reuters, he described the proposed 75-strong ceasefire monitoring team as “a nimble presence” to monitor compliance of the deal and establish and assess facts and conditions on the ground.

Guterres said the larger monitoring mission would contribute to sustaining a “fragile political process” relaunched by U.N. Yemen envoy Martin Griffiths.

Griffiths told the Security Council last week that both sides had largely stuck to the ceasefire but substantial progress would be needed before more peace talks could be held.