US equity indexes ended lower on Monday as crude oil prices rose amid escalating attacks by the US and Iran in the Middle East and the Houthis declaring a blockade of Saudi Arabian oil shipments.

* Iran said mediators have been in touch with proposals on how to ease hostilities with the US after nine days of clashes, while tensions remained high after a threat by the Tehran-backed Houthi group against Saudi Arabia, Bloomberg reported. Houthis in Yemen said Monday they were imposing a naval blockade on Saudi Arabia, Reuters reported.

* The Conference Board's measure of leading indicators declined by 0.2% in June, larger than the 0.1% decrease expected in a Bloomberg-compiled survey.

* August West Texas Intermediate crude oil rose $0.45 to settle at $82.94 per barrel, while September Brent crude, the global benchmark, was last seen up $0.78 at $88.88.

* Global Payments' (GPN) improved buyback capacity, constructive channel checks on the Genius platform and the Worldpay business, low bar for execution, and rising investor interest create a meaningful rerating potential, Morgan Stanley said in a Monday research note. Shares were up 5.8%, the top gainer on the S&P 500.

* Honeywell Aerospace (HONA) shares were down about 4.3%, the worst performer on the Nasdaq, after UBS initiated the stock with a neutral rating and a $231 price target. The company also said it has signed new contracts to deliver its Surface Alerts runway safety technology to Aeromexico.