The Saudi-led coalition's assault on the rebel-held port city of Hodeida is the latest attempt to break years of stalemate in Yemen's devastating civil war.
The conflict pits the U.S.-supported coalition and the internationally recognized government against Shiite rebels known as Houthis, who are allied with Iran. The Houthis swept into Yemen's capital, Sanaa, in 2014 and the coalition entered the war the following year.
The fighting has killed more than 10,000 people, displaced 2 million and driven the Arab world's poorest country to the brink of famine. Aid groups warn that the attack on Hodeida, the country's main entry point for food and humanitarian aid, could make a catastrophic situation even worse.
Here are some key events:
September 2014: The Houthis, allied with forces loyal to former president Ali Abdullah Saleh, seize Sanaa.
February 2015: The Houthis appoint a presidential council, known as the Supreme Political Council, to replace President Abed Rabbo Mansour Hadi, who flees to the southern city of Aden.
Mar. 23, 2015: The battle for Aden begins. The rebels and their allies seize control of Aden International Airport and Hadi flees to Saudi Arabia.
Mar. 26, 2015: A Saudi-led coalition, backed by the United States, begins an air campaign against the Houthis and imposes a naval blockade.
April 2015: The U.N. Security Council imposes an arms embargo on the Houthis and demands they pull back from territory they have captured.
May 5, 2015: Houthi rebels fire mortar rounds and rockets at the Saudi city of Najran, near the border, killing at least three civilians, in one of the first of a series of cross-border attacks.
May 2015: More than 100,000 people flee the northern province of Saada, the heartland of the Houthis, after the coalition declares the entire province a military target.
June 2015: A U.S. airstrike kills al-Qaida's number 2, the head of its Yemeni branch, Nasir al-Wahishi.
September 2015: Hadi returns to Aden after Saudi-backed government forces retake the port city.
April 2016: U.N.-sponsored talks between the government and the rebels begin.
May-June 2016: The Islamic State group claims responsibility for a number of attacks, including a suicide car bombing that killed at least 40 army recruits in Aden.
August 2016: The coalition closes Sanaa airport to commercial flights.
October 2016: An airstrike by the Saudi-led coalition hits a crowded funeral in Sanaa, killing at least 140 mourners.
January 2017: A U.S. raid kills several suspected Al-Qaeda operatives and civilians in America's first military action in Yemen under President Donald Trump.
May 2017: The Houthis say they fired a ballistic missile at the Saudi capital, Riyadh.
June-November 2017: Cholera outbreak in Yemen kills 2,100 and infects almost 900,000.
November 2017: The coalition imposes a complete blockade on Yemen in response to a missile fired by the Houthis at the Riyadh airport. On Nov. 22, the coalition announces a partial lifting of the blockade.
December 2017: Houthis kill former president Saleh after days of street fighting in Sanaa. Days earlier, Saleh had reached out to the Saudi-led coalition, indicating he might switch sides.
April-May 2018: Fighting escalates along the western coast.
June 7, 2018: The International Committee of the Red Cross says it has pulled 71 staff members out of Yemen after a series of incidents and threats.
June 10, 2018: Saudi Arabia says three civilians in the kingdom's south have been killed by incoming fire from Yemen's rebels.
June 12, 2018: Hadi visits the United Arab Emirates, meeting with Abu Dhabi's powerful crown prince, Mohammed bin Zayed Al Nahyan for the first time. The UAE and Hadi are both members of the coalition, but have had tense relations for months.
June 13, 2018: The coalition launches an offensive on the port city of Hodeida.Copyright 2018 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.