Iran's supreme leader called the military intervention by its main regional rival, Saudi Arabia, in Yemen as genocide, sharply escalating Tehran's rhetoric against the two-week-old campaign of airstrikes.
Ayatollah Ali Khamenei said Saudi Arabia would not win the war in Yemen, where Iran-allied Houthi fighters who control the capital Sana’a have been trying to seize the southern city of Aden from local militias.
Tensions are high in Yemen due to the conflict between Houthi rebels and forces loyal to the country's internationally backed president, Abd-Rabbu Mansour Hadi.
Iran has repeatedly urged a halt in the airstrikes and called for dialog in Yemen.
“The aggression by Saudi Arabia against Yemen and its innocent people was a mistake. ... It has set a bad precedent in the region,” Khamenei said in a televised speech. “This is a crime and genocide that can be prosecuted in international courts.”
Iranian President Hassan Rouhani also criticized the coalition assembled by Riyadh, saying it was repeating errors committed in other parts of the Arab world where Sunni Saudi Arabia and Shi'ite Iran back rival sides.
Rouhani called for an end to airstrikes in Yemen by Saudi Arabia and Arab allies, saying they could not succeed, and said countries in the region should work toward a political solution.
“A great nation like Yemen will not submit to bombing. Come, let us all think about ending war. Let us think about a cease-fire,” Rouhani said in a televised speech on Thursday.
“Let us prepare to bring Yemenis to the negotiating table to make decisions about their future. ... Let us accept that the future of Yemen will be in the hands of the people of Yemen, not anyone else,” Rouhani continued.
Khamenei and Rouhani were speaking a day after Iran said it was sending two warships to sea off Yemen.
Iranian Rear Admiral Habibollah Sayyari said the fleet will provide safety for "Iran's shipping lanes" and protect the country's "interests in the high seas." He said it also will seek to keep commercial ships safe from pirates.
U.S. Secretary of State John Kerry said Washington is "very concerned" about Iran's support for Shi'ite rebels in Yemen, and reports that an Iranian naval fleet was headed near the Persian Gulf country.
Houthi-backed forces are believed to be holding Norwegian freelance journalist Raymond Lidal. The Committee to Protect Journalists called for Lidal's immediate release, stressing the importance of "independent reporting" of the conflict. Lidal was detained March 28.
Speaking on the PBS Newshour, Kerry said the U.S. was closely monitoring Iranian support for the rebels, including "supplies that have been coming from Iran" and "a number of [Iranian] flights every single week" into Yemen.
"We're well aware of the support that Iran has been giving to Yemen. And Iran needs to recognize that the United States is not going to stand by while the region is destabilized or while people engage in overt warfare across lines, international boundaries and other countries," he said.
Saudi Arabia and others have accused Iran of training and equipping the Houthi rebels in Yemen. Iran has repeatedly denied the charge.
Iranian Foreign Minister Mohammad Javad Zarif also called on Pakistan Thursday to work toward a political solution in Yemen during a visit to Islamabad, after Saudi Arabia asked Pakistan to join the coalition.
Zarif, who arrived in Islamabad on Wednesday, has said that Iran is ready to facilitate talks that would lead to a broad-based government in Yemen.
Pakistan's parliament is debating whether to contribute forces to the Saudi-led air campaign in Yemen. A government statement released after the meeting with Zarif said Pakistan would stand "shoulder to shoulder" with Saudi Arabia if its territory were violated but called on Muslim countries to "council restraint and promote a spirit of mutual accommodation."
Meanwhile, Shi'ite rebels and allied military units in Yemen defied Saudi-led airstrikes to seize Ataq, a provincial capital in a heavily Sunni tribal area on Thursday.
The rebel fighters, known as Houthis, along with military units loyal to former autocrat Ali Abdullah Saleh, overran Ataq, capital of the oil-rich southeastern Shabwa province, after days of airstrikes and clashes with local Sunni tribes. The capture marked the rebels' first significant gain since the Saudi-led bombing began.
The Saudi-led coalition has imposed an air and sea blockade on Yemen and targeted both rebels and military units loyal to Saleh, hoping to eventually allow Hadi to return to the country. Hadi fled last month to Riyadh.
Southern port city
Shi'ite rebels and their allied troops also had extended their operations by Thursday into the central part of the city of Aden, and the largely Sunni Muslim southeastern areas of the country.
Saudi coalition spokesman General Ahmed al-Asiri on Thursday denied the advance, stating that "small units that are isolated" had moved forward, and that they would be eliminated. He said communication links between rebel units had been cut.
Al-Asiri accused the Houthi rebels of storing weapons in residential areas, and warned that those also would be destroyed.
According to the French news agency AFP, Saudi-led forces on Thursday bombed the defense ministry building in the capital, Sana'a, one of a series of air raids against rebel positions around the city.
The Houthis and their allies have seized 10 of Yemen's 21 provinces but could encounter resistance in Shabwa from al-Qaida in the Arabian Peninsula, which also maintains a heavy presence in the province.
AQAP has taken advantage of the chaos, gaining ground. The Saudi-led bombing threatens to weaken the rebels and Saleh's loyalists, who are al-Qaida's most powerful opponents on the ground.
Meanwhile, humanitarian groups say they are running out of medical supplies to deal with the constant flow of casualties, particularly in Aden, where the fighting is most intense.
The groups have called for a temporary halt to the fighting to allow aid into Yemen. The World Health Organization said Wednesday that at least 643 civilians and combatants have been killed since March 19. At least 2,226 have been wounded, and another 100,000 have fled their homes.
The Red Cross and United Nations children's agency UNICEF were trying to fly aid shipments into Sana’a Thursday.
UNICEF has warned that rates of acute malnutrition in children could soar in coming weeks and threaten the lives of more than 250,000 children in Yemen.
Some material for this report came from AP and Reuters.