Yemen's Shiite rebels intensified attacks against pro-government forces on Saturday in the southern city of Taiz, as they pushed to seize a strategic mountain and landmark positions in the city ahead of scheduled peace talks, security officials said.

The fighting in Yemen's third-largest city left 14 people dead and 27 wounded, with the toll including both fighters and civilians, said the officials, who remain neutral in a conflict that has splintered security forces.

The conflict in Yemen pits the rebels known as Houthis and troops loyal to former President Ali Abdullah Saleh against southern separatists, local and tribal militias, Sunni Islamic militants and loyalists of exiled President Abed Rabbo Mansour Hadi.

The conflict has killed more than 4,000 people, leaving the Arab world's poorest country in the grip of a humanitarian crisis and on the brink of famine.

The Houthis are aiming to take the Jarrah mountain that overlooks many neighborhoods in Taiz, as well as reclaim Taiz's presidential palace, the nearby former residence of Saleh and a judicial compound, the officials said. Pro-government forces backed by airstrikes from a Saudi-led coalition have pushed the Houthis out of much of the country's south in recent weeks.

The ramped-up attacks come as the Houthis, Yemen's government in exile and the country's former ruling party are set to meet for U.N.-brokered peace talks in the coming days.

"Intensifying the attacks before the resumption of talks with the government is the Houthis' way of saying, 'We are still strong on the ground'," said independent political activist Abdullah al-Mokhalafi.

Meanwhile, in Taiz's pro-Hadi camp, forces have asked the Saudi-led coalition for reinforcement, citing a shortage of weapons.

Also Saturday, a suspected U.S. drone attack killed four people believed to be al-Qaida militants who were traveling in a vehicle between the central province of Marib and the desert province of Jawf bordering Saudi Arabia, independent security officials and local tribal leaders said. The bodies of the suspected militants were found charred, the tribal leaders added.

All officials and tribal leaders spoke on condition of anonymity because they are not authorized to brief reporters or fear reprisals.