Stock markets retreated in sparse summer trading Friday, with the uncertain outlook for the Middle East war and the US economy prompting investor caution ahead of the weekend.

US stocks are slipping below their records, while oil prices keep swinging on uncertainty about when the war with Iran will allow crude to flow freely again.

Wall Street closed lower as investors grew pessimistic about Middle East stability. Amazon and Alphabet stocks dipped, impacting major indices like the S&P 500. Brent crude…