Two UN contractors detained in Houthi-controlled Sanaa

Two contractors working for the United Nations have been detained in Yemen, a UN spokesman said on Saturday, but he declined to confirm that the pair were Americans.

"It concerns two contractors. I cannot confirm their nationalities," said UN spokesman Farhan Haq.

Haq said officials from the UN department of safety and security were dealing with the matter.

The US State Department said it was looking into reports that two US nationals were detained in Sanaa, which is under the control of the Houthi militia and its allies.

"We are aware of reports that two US citizens have been detained at Sanaa airport in Yemen," a State Department official said.

"The protection of US citizens overseas is one of the Department of State's highest priorities, including in these cases."

The State Department declined to provide more details, citing privacy considerations.

The United Nations is trying to organize peace talks between the Saudi-backed Yemeni government and Houthi militia, which are backed by forces loyal to former president Ali Abdullah Saleh.

A Saudi-led coalition launched an air campaign in March to push back the Iran-backed Houthis and restore the authority of the government.

The United Nations is increasingly alarmed at the heavy toll on civilians, with 80 percent of the population in dire need of aid.

Gunmen kill two Yemen security officers in Aden

Meanwhile, gunmen killed two security officers in separate drive-by shootings in the southern Yemeni city of Aden, security officials said on Sunday.

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

Gunmen shot dead Abdelwahed 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 neighbouring Lahj province, Saeed Abdullah, escaped an attempt to assassinate him in a similar way in Aden, a third security official told AFP.

All the attacks took place late on Saturday, the sources said.

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.

Dozens killed as government forces clash with Houthis

Dozens of Houthi militiamen and pro-government fighters have been killed in clashes in several southern provinces as Saudi-led coalition aircraft targeted the Iran-backed militia, military officials said on Saturday.

Fierce clashes raged in the areas of Al-Zaher and Thi al-Naem in Baida province between Houthi militiamen and Popular Resistance fighters allied with forces loyal to President Abd Rabbuh Mansour Hadi, tribal sources said.

The clashes overnight left 19 rebels and 14 Popular Resistance fighters dead, according to tribal and medical sources.

Gun battles also flared up in Al-Madaribah in southwestern Yemen on the border between Lahj and Taiz provinces, leaving an unknown number of fighters killed and wounded, military sources said.

Southern fighters said they were defending the area against militiamen trying to reach the shores of the strategic Bab al-Mandab strait, some 50 kilometres (30 miles) away, which was seized by loyalists last month.  

The narrow waterway, which separates Yemen from Djibouti, funnels shipping to and from the Suez Canal in the northern Red Sea.

Witnesses said that many residents fled the area due to heavy fighting.

Warplanes from a Saudi-led coalition raided positions of Houthis and allied renegade troops loyal to Saleh, military officials said.

The air strikes destroyed Houthi vehicles in the central Ibb province, close to Daleh, which was seized by pro-government forces along with four other southern provinces earlier this year.