Jemen - AP

This Aug. 7, 2018 photo shows mountains in Hadramout, Yemen. (AP Photo/Nariman El-Mofty)

Boys ride on the back of a truck in Sanaa, Yemen on Aug. 6, 2018. (AP Photo/Nariman El-Mofty)

This Aug. 6, 2018 photo shows mountains in Bayda, Yemen. (AP Photo/Nariman El-Mofty)

This Aug. 3, 2018 photo shows a damaged vehicle abandoned on a road in Ibb, Yemen. (AP Photo/Nariman El-Mofty)

A man drives a damaged vehicle on a street in Ibb, Yemen, on Aug. 3, 2018. (AP Photo/Nariman El-Mofty)

This Aug. 3, 2018 photo shows paint on a roadside wall with Arabic that reads, "Boycott America, Muhammad, God is great. Death to America. Death to Is...

A farmer leads her sheep along the side of a mountain in Ibb, Yemen, on Aug. 3, 2018. (AP Photo/Nariman El-Mofty)

A man walks down a road in Ibb, Yemen, on Aug. 3, 2018. (AP Photo/Nariman El-Mofty)

A donkey forages on the roadside in Ibb, Yemen, on Aug. 3, 2018. (AP Photo/Nariman El-Mofty)

Men chew qat, a narcotic leaf, as they ride motorbikes in Ibb, Yemen, on Aug. 3, 2018. (AP Photo/Nariman El-Mofty)

This Aug. 3, 2018 photo, shows an ancient site, top, known as Samara Castle, in Ibb, Yemen. (AP Photo/Nariman El-Mofty)

This Aug. 3, 2018 photo shows a highway running through mountains in Ibb, Yemen. (AP Photo/Nariman El-Mofty)

Boys stand next to the dilapidated remains of a van with four flat tires half-sunk in the dirt on a mountain in Ibb, Yemen on Aug. 3, 2018. (AP Photo/...

This Aug. 3, 2018 photo shows a green mountain landscape, where the terraces were planted with corn, barbary figs and qat, in Ibb, Yemen. (AP Photo/Na...

In this Aug. 3, 2018 photo, women walk on a road in Ibb, Yemen. (AP Photo/Nariman El-Mofty)

This Aug. 3, 2018 photo shows a damaged vehicle on the roadside in Ibb, Yemen. (AP Photo/Nariman El-Mofty)

This Aug. 3, 2018 photo shows the Houthi slogan with Arabic that reads, "God is great. Death to America. Death to Israel. Curse the Jews. Victory to I...

This July 31, 2018 photo shows mountains along a road in Bayda province, Yemen. (AP Photo/Nariman El-Mofty)

This July 30, 2018 photo shows a damaged billboard with Arabic that reads, "Yemen is in our hearts," in Marib, Yemen. (AP Photo/Nariman El-Mofty)

A beggar woman stands in the middle of a highway in Bayda province, Yemen, on July 31, 2018. (AP Photo/Nariman El-Mofty)

A goat forages on a highway in Bayda province, Yemen, on July 31, 2018. (AP Photo/Nariman El-Mofty)

A boy poses for a photograph at a displaced persons camp in Marib, Yemen on July 29, 2018. (AP Photo/Nariman El-Mofty)

A group of men stand together for a photo at a displaced persons camp in Marib, Yemen, on July 29, 2018. (AP Photo/Nariman El-Mofty)

African migrants walk down a highway in Marib, Yemen on July 29, 2018. (AP Photo/Nariman El-Mofty)

This July 30, 2018 photo shows the ancient Bilqis Temple (Sanctuary of the Queen of Sheeba), in Marib, Yemen. (AP Photo/Nariman El-Mofty)

A boy takes a "selfie" photo at the Marib Dam in Yemen on July 30, 2018. (AP Photo/Nariman El-Mofty)

Women stand near the water's edge at the Marib Dam in Yemen on July 30, 2018. (AP Photo/Nariman El-Mofty)

A boy collects water from a fountain on a roadside in Marib, Yemen on July 29, 2018. (AP Photo/Nariman El-Mofty)

A girl leans on a car window as she begs on the street in Marib, Yemen, on July 27, 2018. (AP Photo/Nariman El-Mofty)

Men gather under trees in Shabwa, Yemen, on July 24, 2018. (AP Photo/Nariman El-Mofty)

This July 24, 2018 photo shows the al-Qaida flag painted on rocks near the southern flag with Arabic that reads, "Yes to liberating the south," and "t...

In this July 24, 2018 photo, a group of women walk through Shabwa, Yemen. (AP Photo/Nariman El-Mofty)