ref. https://www.bbc.com/news/world-middle-east-46040789

The US has called for a swift cessation of hostilities in Yemen, where three years of civil war have caused the world's worst humanitarian crisis.

* swift :  adj. Happening quickly or promptly / moving or capable of moving at high speed  adv. swiftly

* humanitarian : adj. concerned with or seeking to promote human welfare

Defence Secretary James Mattis said (that) all parties needed to take part in UN-led peace talks within the next 30 days.

Secretary of State Mike Pompeo (meanwhile) urged / the Saudi-led coalition [ battling the rebel Houthi movement ] / to end its air strikes on populated areas.

* coalition : A temporary alliance for combined action, especially of political parties forming a government.

The US has faced / growing pressure / to end its support for the coalition.

UN human rights experts say (that) coalition forces may have committed war crimes in Yemen // and humanitarian organizations say their partial blockade of the country has helped push 14 million people to the brink of famine.

* blockade : n. an act or means of sealing off a place to prevent goods or people from entering or leaving. / an obstruction of a physiological or mental function, especially of a biochemical receptor.

                   verb. seal off (a place) to prevent goods or people from entering or leaving

* run a blockade : (of a ship) manage to enter or leave a blockaded port

     ​vessels suspected of running the UN blockade

* receptor : an organ or cell able to respond to light, heat, or other external stimulus and transmit a signal to a sensory nerve.

* famine : extreme scarcity of food / a shortage / hunger

The murder of the US-based journalist Jamal Khashoggi by Saudi agents in Istanbul this month / has (also) strained ties between Washington and Riyadh.

* strain : verb.  1. force (a part of one's body or oneself) to make an unusually great effort.  ​I stopped and listened, straining my ears for any sound.​  2. make an unusually great effort  ​His voice was so quiet that I had to strain to hear it.​  3. injure (a limb, muscle, or organ) by overexerting it.  ​On cold days you are more likely to strain a muscle.​  4. make severe or excessive demands on.  ​He strained her tolerance to the limit​.  5. pull or push forcibly at something.  6. stretch (something) tightly  7. pour (a mainly liquid substance) through a porous or perforated device or material in order to separate out any solid matter.  8. cause liquid to drain off (food which has been boiled, soaked, or canned) by using a porous or perforated device   9. drain (liquid) off food by using a porous r perforated device

  Why is there a war in Yemen?

  Yemen has been devastated by a conflict that escalated in early 2015, when the Houthis seized control of much of the west of the country and forced President Abdrabbuh Mansour Hadi to flee abroad.

  Alarmed by the rise of a group they saw as an Iranian proxy, the UAE, Saudi Arabia and seven other Arab states intervened in an attempt to restore the government. They have received logistical and intelligence support from the US, UK and France.