SANAA/ADEN: At least five air strikes hit military sites and an area near the presidential palace compound in the Yemeni capital Sanaa at dawn on Sunday while warships pounded an area near the port of the southern city of Aden, residents said.

The bombings were the first raids on Sanaa since a Saudi-led alliance said last week it was scaling back a campaign against Iranian-allied Houthi militias, which control Sanaa and have powerful allies in Yemen's factionalised armed forces.

“The explosions were so big they shook the house, waking us and our kids up. Life has really become unbearable in this city,” a Sanaa resident who gave his name as Jamal told Reuters.

Read: Saudi-led coalition launches fresh strikes; fighting erupts in Yemen

Eyewitnesses in Aden said foreign warships pounded Houthi armed positions around the city's main commercial port and dockyard, the first time the port area has been shelled, residents said.

Aden residents reported heavy clashes between local armed militia and Houthi fighters backed up by army units, and sources in the militia said they were retaliating for the first time with tank and Katyusha rocket fire against the Houthi advance.

In the southern province of Dalea, the militiamen said they had fought for hours to retake several rural districts with the help of Saudi-led air strikes, in fighting which left around 25 of the Houthi forces and six of their own men dead.

Saudi Arabia, the world's top oil exporter and arch regional adversary of Iran, is concerned about possible security threats posed by the Houthis' advance across Yemen since last September.

It launched a month-long campaign of air raids against the group that has halted its battlefield progress but has yet to reverse their dominant position in the country or force them to return to peace talks.

Read: Clashes, air strikes leave over 90 dead in southern Yemen

Saudi air strikes embolden armed opposition forces

A group of tribal and Islamist fighters in the strategically important central Yemeni city of Taiz on Sunday took back several districts from the Iran-allied Houthi militia amid heavy fighting, residents said.

The reverses deal a blow to the Houthis in an area they have controlled largely unopposed for more than a month.

They may be a sign that more than a month of Saudi-led air strikes against Houthi forces have emboldened armed opposition groups.

Read: Yemen rebels demand complete end to attacks, seek talks

New UN envoy to kickstart peace talks

A new United Nations envoy was looking to kickstart peace talks in Yemen as battles raged Sunday between Iran-backed rebels and pro-government forces a month after the launch of Saudi-led air strikes.

The Shiite Houthi rebels, who have overrun large parts of the country and forced President Abd-Rabbu Mansour Hadi to flee abroad, have demanded an end to the air strikes as a condition for UN-sponsored talks.

The United Nations on Saturday confirmed Mauritanian diplomat Ismail Ould Cheikh Ahmed as the new special envoy to Yemen, replacing Moroccan Jamal Benomar, who resigned last week following what diplomats described as sharp criticism of his performance by Gulf countries.

Ould Cheikh Ahmed “will work closely with the members of the United Nations Security Council, the Gulf Cooperation Council, governments in the region and other partners, as well as the United Nations country team for Yemen,” a UN statement said.

Former strongman Ali Abdullah Saleh, who still holds sway over army units allied with the Shiite rebels, late Friday urged the Houthis to heed UN demands to withdraw from territory they have seized.

US Secretary of State John Kerry also called on anti-government forces to enter into political dialogue to end a conflict that the United Nations says has killed more than 1,000 people since late March.

The fighting has raised fears that Yemen could become a front in a proxy war between Sunni-ruled Gulf monarchies and Shiite Iran.

Read: Yemen’s ex-president urges allies to implement UN decisions