MANAMA / ADEN / UNITED NATIONS: The U.N. special envoy to Yemen said Sunday he expected talks between its warring parties to begin by mid-November, eight months after the start of a messy civil war that has killed thousands and caused a humanitarian crisis.

The conflict pits the Iran-allied Houthi militia and army units loyal to former President Ali Abdullah Saleh against armed groups who support exiled President Abed Rabbou Mansour Hadi alongside an Arab coalition.

“I expect that before mid-November, God willing, a date will be specified and I expect that the dialogue must begin before mid-November, as a minimum, Nov. 15,” U.N. envoy Ismail Ould Cheikh Ahmed told Reuters in Bahrain.

All major combatants have publicly agreed to implement U.N. Security Council Resolution 2216, which calls on Houthi and Saleh forces to withdraw from main cities and surrender arms captured from Yemeni government forces.

However, while Hadi and the coalition have previously demanded that this happen before talks begin, the Houthis and Saleh want talks to address mechanism for Resolution 2216 to be implemented. Discussions between the United Nations and the Houthis have taken place already in Oman’s capital Muscat.

“I have a team in Riyadh and before that they were in Muscat, exactly to reach agreement on the date and venue and the subjects that will be discussed within the context of U.N. Security Council Resolution 2216,” Ould Cheikh Ahmed said.

He added that a statement Friday by a senior Houthi leader that efforts to find a political solution had failed did not appear to represent the group’s official position.

Saudi Foreign Minister Adel al-Jubeir said Saturday that he believed the coalition’s Yemen campaign was in its “final phase” after military gains against the Houthis and given their willingness for talks.

However, the Houthis and Saleh’s forces still hold most of the country’s western highlands, its most populous region including the capital Sanaa. Ould Cheikh Ahmed said he did not believe the coalition intended to take Sanaa by force.

“I can say simply what I have been told, but I can’t speak for the coalition. I don’t think anybody has any intention to enter into Sanaa. People prefer to have a political solution.”

In the southern port of Aden which the coalition and local forces took back from the Houthis in July, unidentified assailants killed two security officers in separate drive-by shootings late Saturday, security officials said Sunday.

In the first incident, gunmen opened fire from a car at Maj. Meead Ali outside the building where he lives in the port city’s Inmaa neighborhood, one official said.

Gunmen shot dead Abdel-Wahed Ahmed of Aden’s criminal investigation unit in a similar attack outside his home in Al-Mansura district, another security official said.

Meanwhile, the chief prosecutor of the neighboring Lahej province, Saeed Abdullah, escaped an attempt to assassinate him in a similar way in Aden, a third security official told AFP.

Such assassinations by unidentified gunmen in cars or on motorbikes are common in Yemen, especially in the lawless south and are usually attributed to Al-Qaeda, although it rarely claims responsibility for them. Islamist militants, including Al-Qaeda and ISIS, appeared to have gained ground in the southern city, where militants have become visibly present.

The United Nations said Saturday two contractors with the world body had been detained in Yemen, but gave no further details on the incident. “Two contractors have been detained and DSS [Department of Safety and Security] is looking into it,” a U.N. spokesman said without elaborating or confirming if the two were American citizens.

A U.S. State Department official said it was aware of reports that two U.S. citizens had been detained at Sanaa airport in Yemen.

“The protection of U.S. citizens overseas is one of the Department of State’s highest priorities, including in these cases,” the official said in an email. “Due to privacy considerations, we do not have any further information to share.”

The United Nations has designated Yemen as one of its highest-level humanitarian crises, alongside emergencies in South Sudan, Syria and Iraq. It says more than 21 million people in Yemen need help, or about 80 percent of the population.