Citing CBS, Iran foreign minister Araghchi said Iran will not accept a ceasefire during a US–Iran war and will only accept an end to the conflict. He said: We have told mediators we will not accept a ceasefire; the war must end. He added the war must end in a way that prevents it from happening again.

UK Prime Minister Burnham on Aug. 18 confirmed he exchanged messages with someone impersonating White House chief of staff Susie Wyles. Burnham said the exchanges were very brief, contained no sensitive material, and he reported the incident promptly. US President Trump told reporters on Aug. 17 he viewed it as a "communication misunderstanding" and said he has had several "good talks" with Burnham.

China A-shares domestic operating-system sector briefly rallied; Chengmai Technology rose over 9%, China Software gained over 5%, Feitian Technologies, Shensi Electronics and Transsion Holdings also advanced.