Bombings struck the rebel-held presidential palace in Aden’s downtown area.
Explosions could be heard near Aden’s airport and the districts of Khor Maksar and Crater, a witness said.
The five-day humanitarian truce began on Tuesday to distribute aid to the millions deprived of food, fuel and medicine by weeks of fighting.
The money would be in addition to another SAR1 billion the monarch had pledged, Al Arabiya said.
A military coalition led by Saudi Arabia has imposed inspections on all ships entering Yemen.
The five-day humanitarian truce in Yemen came into effect at 11 pm on Tuesday.
Residents said three air strikes hit a base for army units loyal to the Houthis in the north of the capital.
Yemen’s Houthi militia said tribesmen shot down the aircraft.
Saudi Arabia has offered a five-day ceasefire starting on Tuesday evening to allow delivery of humanitarian supplies into the country.
The pilot of a second jet in the same squadron could not see if the pilot had ejected from the jet.
A statement issued by the Houthis also asked for a political dialogue under the auspices of the United Nations to resume in order to resolve the conflict.
Scores of civilians were reportedly killed and thousands forced to flee their homes after the coalition declared the entire governorate a military target.
US Secretary of State John Kerry, who is visiting Riyadh, welcomed the proposal.
US Secretary of State John Kerry began negotiations in Riyadh on Thursday to pause the campaign of airstrikes launched by a Saudi-led coalition on March 26.
One shell landed near security forces patrolling near the prison in Najran, killing an officer, while another killed four Saudi civilians.
U.S. Secretary of State John Kerry said the United States was deeply concerned with the worsening humanitarian conditions in Yemen.
A Saudi-led Arab alliance has been conducting air strikes against Houthi fighters in Yemen since late March.
The projectiles struck a girls’ school and a hospital in Najran, which is only two miles from Yemen’s border, officials said.
The statement comes as the UN prepared a plan to set up an air-bridge to bring humanitarian workers into the country.
The aircraft also targeted a camp of forces loyal to former president Ali Abdullah Saleh, in Arhab district north of the city.
The United Nations says the conflict in Yemen has killed 600 people, wounded 2,200 and displaced 100,000 since September.
Private Gharbi Rajah al-Hassan al-Mujaishi was patrolling on Thursday morning in the Hareth sector in Jizan province when he was killed.
Yemenis warn that the longer the fighting lasts, the harder it will be to restore meaningful state control.
So far the fighting and air strikes have killed over 1,000 people since the bombings started on March 26.
A spokesperson said that the country will present a plan in Saudi Arabia next month, requesting membership into the GCC.
An NGO has filed a complaint with the public prosecutor accusing 39 prominent figures, including Tawakul Karman, of treason.
Iran said the plane was carrying humanitarian aid to Sanaa.
Riyadh announced last week that it was ending its nearly five-week-old bombing campaign, except in places where the Houthis were advancing.
Riyadh now faces a test of its diplomatic skills in trying to arrange talks among Yemen’s fractious elites.
Saleh said he was ready to reconcile with all parties that have opposed him since 2011 “for the interest of the nation”.