Egypt's military says Saudi and Egyptian warships deployed Friday to the Bab al-Mandab strait off Yemen's coast to secure the strategic passage, as a Saudi-led coalition carried out airstrikes on rebel targets in Yemen for a second straight day.
Military officials told the Associated Press that Saudi and Egyptian vessels were at or near the strait.
Bab al-Mandab is a critical waterway for Egypt's national security and is the main entrance for access to the Red Sea en route to the Suez Canal, a key route for shipping between Europe and Asia.
On Friday, Saudi-led coalition airstrikes pounded military bases and other Shi'ite Houthi rebel targets in and around the capital, Sana'a, where witnesses said jets struck at parts of the presidential palace complex, destroying a number of buildings. Military officials said airstrikes also targeted the northern province of Saada, home to the Houthi rebels.
Some two dozen civilians are believed to have been killed in the wave of airstrikes; video from the scene showed the bodies of children being pulled from the rubble.
Coalition planes also were reported to have struck a Houthi radar installation in Maarib province and an airbase in Abyane province.
The commander of the Saudi-led operation insisted that airstrikes were being conducted with precision, dismissing evidence of civilian casualties.
He said that at present, no troops were being deployed on the ground, but if the need arose, Saudi ground troops, as well as those of friends and allies, were ready and would respond to any aggression.
A Saudi military spokesman said the Saudi-led airstrikes against Houthi rebels would continue as long as needed to protect the Yemeni government.
The White House said President Barack Obama spoke with Saudi King Salman by telephone Friday. The president said he backed the Gulf allied military action in Yemen, but that he and the king agreed that a negotiated political settlement was their goal.
Also Friday, U.S. officials said an American military helicopter rescued two Saudi pilots who had ejected from their jet over the Gulf of Aden.
The Saudis asked the Americans for help. It was not clear why their plane went down. It was also unclear whether the pilots were hurt, but witnesses said they were able to walk after being rescued.
Meanwhile, Yemeni President Abd-Rabbu Mansour Hadi arrived in Egypt on Friday for a two-day summit in the Red Sea resort of Sharm el-Sheik that will begin Saturday and will likely be dominated by the crisis in Yemen.
The rebel advance through Yemen prompted Hadi to flee the country earlier this week. His location was unknown until Thursday, when he reappeared in the Saudi capital, Riyadh.
Saudi Arabia is leading a regional effort to oust the Shi'ite Houthi group that has taken over much of the country. A coalition of 10 countries, including five Gulf monarchies, is trying to defeat the Iran-backed Houthis and reinstall Yemen's internationally recognized government.
Iran, which denies funding and training the Shi'ite Houthis, has slammed the Saudi-led offensive as a dangerous step that will worsen the situation in Yemen.
On Friday, Iranian Foreign Minister Mohammad Javad Zarif said the airstrikes had to stop and that they would only cause the loss of lives. He called for dialogue and national reconciliation in Yemen.
Yemen's acting foreign minister, Riyadh Yasin, said the airstrikes should weaken the Shi'ite Houthi rebels. He said he hoped the operation would accomplish its goals quickly and that it would end soon.
Pakistan — Saudi Arabia's longtime ally — said Friday that it had not yet decided to join the coalition. Defense Minister Khawaja Asif told parliament Islamabad was ready to defend Saudi Arabia's territorial integrity "at any cost," but did not want to involve itself in a sectarian war.
Also Friday, the Arabic television network Al Jazeera condemned an attack by Houthi rebels on its bureau in Sana'a. The network said armed Houthis stormed the bureau, with guards reporting that the rebels destroyed security cameras, smashed the entrance door and ransacked the office contents.
Rebel leader Abdul Malik al-Houthi on Thursday blasted Saudi Arabia, as well as the United States, which is offering "logistical and intelligence support" to the offensive.
"The foolish, stupid, unjust, oppressive and arrogant Saudi regime has gambled [on the support of] America and gambled on some other regimes, which it paid to buy their support," the rebel leader said.
Houthi officials said at least 18 people had been killed and 24 wounded in the Thursday airstrikes. There was no immediate word on casualties from the Friday bombings.
Yemen has sunk into violence and chaos since a popular uprising ousted longtime strongman President Ali Abdullah Saleh in 2012.
The Houthis, who are now allied with Saleh, have taken over the capital and have battled Sunnis and various tribes as they try to advance throughout the rest of the country.
Some information for this report came from AP, AFP and Reuters.