One British and one American citizen have been killed in Ukraine’s war against Russia this week.Scott Sibley, identified as a 36-year-old military veteran by British media, is believed to be the first Briton to die fighting in the conflict."We can confirm that a British national has been killed in Ukraine," a Foreign Office spokesperson told AFP on Thursday without officially confirming his identity.The Foreign Office added that a second British national is missing, saying “we are urgently seeking further information.” Separately, CNNreported on the death of former U.S.

Marine and private military contractor Willy Joseph Cancel at age 22 on Monday.“He wanted to go over because he believed in what Ukraine was fighting for,” Cancel’s mother Rebecca Cabrera said Thursday.Cabrera said Cancel had agreed to be deployed in Ukraine when the private military contracting company he had worked with was searching for contractors.

CNN did not identify the company.Cabrera said Cancel had crossed into Ukraine from Poland sometime between March 12 and March 13 and fought alongside a group of men from “all different countries.”The State Department said it was “aware of these reports” of Cancel’s death but declined to comment further “due to privacy considerations.”After Russia invaded his country on Feb.

24, Ukrainian President Volodymyr Zelensky called for foreigners to volunteer to fight alongside Kyiv's forces.As many as 20,000 foreign volunteers have reportedly traveled to Ukraine to fight in the country’s so-called “international legion” against Russian forces. Russia is believed to be holding captured British soldiers Shaun Pinner and Aiden Aslin.Britain and the United States have warned their citizens against taking part in the conflict and U.S.

President Joe Biden has maintained that he would not send troops to fight Russia on the side of Ukraine.The Defense Department on Friday reiterated its warning to Americans against going to Ukraine to join the fight against Russia's invasion."We continue to urge Americans not to go to Ukraine...

this is an active war zone, this is not the place to be traveling to," Pentagon spokesman John Kirby told CNN the day after reports emerged of Cancel's death.