(Updates with index/price moves and geopolitical news from the first paragraph.)

US equity indexes declined, with chipmakers helping drive technology to the bottom of sector charts, after the 30-year government bond yield touched levels last seen around the 2007 global financial crisis and crude oil prices extended gains.

The Nasdaq Composite dropped 1.3% to 26,304.5, and the S&P 500 declined 0.6% to 7,698.6 ahead of Tuesday's close. The Dow Jones Industrial Average slipped 0.1% to 53,402.9. Technology and industrials led decliners.

Most US Treasury yields retreated after midday. The 30-year yield fell 2.5 basis points to 5.29% after touching 5.34% intraday, the highest since 2007.

The increase in the 30-year yield to a 19-year high comes amid concerns that an imminent escalation in the Middle East sent Brent crude prices above $90 a barrel and will fan fears of inflation, according to a D.A. Davidson research note Tuesday.

The front-month US West Texas Intermediate crude oil contract rose 0.6% to $85.01 per barrel, and global benchmark North Sea Brent edged up 0.1% to $91.00 per barrel a day after the deadline to reach a permanent peace deal with Iran expired.

"There are no talks or conversations going on, or scheduled, with the Islamic Republic of Iran," President Trump posted on his social media platform.

The Strait of Hormuz will remain closed until the US meets the conditions of an interim deal signed with Iran in June, Reuters reported Tuesday, citing Iran's negotiator Mohammad Baqer Qalibaf in state media.

On the same day, Trump posted an image that showed the Strait of Hormuz as "New U.S. Territory." More than 80% of vessel transits through the Strait of Hormuz over the past two weeks have taken the Omani route - a UN-authorized shipping channel that Iran vehemently opposes - according to Kpler, which tracks ships using transponders and satellite data, CNN reported.