Riyadh: Top US diplomat John Kerry was in Saudi Arabia Thursday to push for a “pause” in air strikes in Yemen while the country’s exiled authorities urged a foreign ground offensive against Al Houthi militiamen.

Weeks of air strikes by a Saudi-led coalition have failed to halt an advance by the Iran-backed Al Houthi militiamen in Yemen and concern has been mounting over increasing civilian deaths and a growing humanitarian crisis.

In a letter to the Security Council on Wednesday, Yemen’s mission to the United Nations said the Al Houthi militiamen were carrying out “barbaric violations” in the southern city of Aden and pleaded for action.

“We urge the international community to quickly intervene by land forces to save Yemen, especially Aden and Taez,” the letter said.

Coalition air strikes and weapons drops have been supporting fighters loyal to President Abd Rabbo Mansour Hadi, who fled Al Houthi advance on his southern refuge in the port city of Aden, where intense combat continues.

Hadi supporters are battling Al Houthis, who have seized large parts of the country including the capital Sana’a. Al Houthis are allied with troops loyal to ex-president Ali Abdullah Saleh.

After arriving in Riyadh on Wednesday, Kerry met powerful Crown Prince Mohammad Bin Nayef.

On Thursday he held talks with Hadi, now based in the Saudi capital, and with his Saudi counterpart Adel Al Jubeir.

Kerry was to cap his visit by meeting King Salman, after Riyadh said it is considering temporary halts in air raids to allow aid deliveries into Yemen.

“We will be discussing the nature of the pause and how it might be implemented,” Kerry told reporters before reaching Riyadh.

“We are deeply concerned about the humanitarian situation that is unfolding in Yemen... For the time being the immediate crisis is the humanitarian one,” Kerry said.

At least 1,200 people have been killed in the country since March 19, roughly half of them civilians, according to the UN.

The new UN envoy for Yemen, Esmail Ould Shaikh Ahmad, was to follow Kerry to Riyadh on Thursday in a bid to relaunch peace talks.

On Wednesday, 38 people were reported to have died while trying to flee Aden by sea.

A health official accused Al Houthi militiamen of killing the civilians and wounding another 95 in the shelling of a fishing harbour and a barge.

As well as the growing civilian death toll from the air campaign and fighting, deliveries of fuel, food and medicine have been severely crippled in the impoverished Arabian Peninsula nation.

Yemen’s Foreign Minister Riyad Yassin appeared to choke up after talking to reporters about the latest casualties in Aden.

There were “many dead bodies that were found in houses and streets” after a rebel attack on the city’s Al Tawahi area, he said in Riyadh on Wednesday.

Yassin added that he hoped to hold talks with Kerry, “especially about the humanitarian aid to Yemen”.

Twenty-two humanitarian organisations warned their emergency aid operations in Yemen could cease because of fuel shortages, and urged an immediate opening of roads as well as an end to the coalition’s air and sea blockades.

Human Rights Watch on Thursday accused pro-Al Houthi forces of committing “possible war crimes”, including their holding hostage 10 aid workers delivering medical supplies in Aden last month. They were later released.

In Saudi Arabia the war hit home for a second day on Wednesday, when four civilians and a prison security officer were killed by shells fired from Yemen at the border city of Najran.

The bombing came a day after Al Houthi militiamen made their first mortar and rocket attack on a Saudi city during the war, killing three people.

“The UK and US are sending mixed messages: officially they support the Saudi-led coalition but privately they say they want a ceasefire,” said Jane Kinninmont, deputy head of the Middle East and Africa programme at the London-based Chatham House think tank.

She told AFP that although the coalition has eliminated some of Al Houthis’ heavy weapons, the air strikes have not brought about a rebel retreat or strengthened Hadi’s position.