An air strike killed dozens of people at a camp for displaced people in northwest Yemen on Monday, aid workers said, as Arab warplanes bombard rebels around the country.
The International Organization for Migration said at least 40 people had been killed and 200 wounded at the Al-Mazrak camp in Hajja province where it has staff on the ground, revising an initial toll of 45 dead.
Medics at a hospital near the camp gave a similar toll.
IOM spokesman Joel Millman said 25 of the wounded were in severe condition.
"It was an air strike," said Pablo Marco of Doctors Without Borders (MSF), which has a presence at the hospital.
The Al-Mazrak camp has since 2009 been housing Yemenis displaced by the conflict between northern Huthi rebels and the central government.
Marco said 500 new families had arrived at the camp in the past two days.
A Saudi-led Arab coalition has been pounding Shiite rebel positions in Yemen since early Thursday.
It has vowed to keep up the raids until the Iran-backed rebels abandon their insurrection against President Abedrabbo Mansour Hadi, who has fled to Riyadh.
Warplanes carried out a fifth night of strikes around the capital Sanaa until dawn on Monday, an AFP correspondent reported.
Coalition air strikes also targeted army bases north of the capital later in the day and residents reported heavy explosions.
At least 12 rebel troops were killed when coalition strikes hit their vehicles as they tried to enter the main southern city Aden from central Bayda province, a military official said.
The Huthis are backed as well by army units loyal to former president Ali Abdullah Saleh, who stepped down in 2012 after a year of bloody protests in the deeply tribal country, where Al-Qaeda is active.
Officials said on Monday that the ex-strongman's son had been sacked as ambassador to the United Arab Emirates, which is part of the coalition.
Ahmed Ali Saleh was relieved of his duties at the demand of the UAE, according to a Gulf diplomatic official who did not want to be named.
The Huthis and allied renegade military units have overrun much of Yemen and prompted Hadi to flee what had been his last remaining refuge in Aden.
Dozens of people have been killed in several days of clashes in the city, and Hadi's aides have said he has no immediate plan to return there.
In the southern town of Daleh, a government official accused pro-Saleh troops of killing eight civilians, including two children, when they opened fire using tanks and artillery.
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- Sea blockade -
Coalition spokesman Ahmed Assiri said the latest strikes targeted depots of ballistic missiles and were also aimed at halting the rebel advance on Aden.
The coalition had imposed a sea blockade and all movements in and out of Yemeni ports would be inspected, he said.
A Chinese naval flotilla, which had been carrying out anti-piracy escort missions in the Gulf of Aden and Somali waters, was sent to Yemen on Sunday to evacuate Chinese nationals, Beijing said.
More than 500 Chinese citizens had been evacuated in two days.
The fighting in Yemen has stoked tensions between Sunni Arab nations and Shiite Iran.
Hadi has branded the Huthis the "puppet" of Tehran, and the prospect of an Iran-backed regime seizing the impoverished Arabian Peninsula state has alarmed its neighbours.
Israeli Prime Minister Benjamin Netanyahu warned Western powers that any nuclear deal struck in talks in the Swiss city of Lausanne would be seen as a reward for Tehran's "aggression" in Yemen.
"One cannot understand that when forces supported by Iran continue to conquer more ground in Yemen, in Lausanne they are closing their eyes to this aggression," he said.
- War of words -
On Thursday, Turkish President Recep Tayyip Erdogan demanded that "Iran and the terrorist groups must withdraw" from Yemen.
He also accused Iran of meddling in other regional states, citing its role advising and coordinating Shiite militias in the fight against Islamic State group jihadists in Iraq.
Iran said it had asked Turkey's top diplomat in Tehran to explain Erdogan's "inappropriate" remarks.
Erdogan said on Monday he still planned to visit Iran despite a war of words with Tehran.
Pakistan renewed its support for Saudi Arabia and said it would send a high-level delegation to the kingdom on Tuesday to assess the situation.
"No decision has been made yet to send Pakistani troops to Saudi Arabia," Defence Minister Khawaja Asif said.
"There are no Pakistani troops, jets or ships in Saudi Arabia. If Saudi Arabia's as a state comes under threat we will surely protect it, but so far Saudi Arabia has no threat," Asif said.