IE 11 is not supported. For an optimal experience visit our site on another browser.

Know It All: Tuesday evening's top stories on NBC News

President Obama addresses the nation on Tuesday.
President Obama addresses the nation on Tuesday.NBC News

Here's a snapshot of some of the top stories we're following Tuesday evening:

Obama: US military ‘doesn’t do pinpricks’

President Barack Obama told the country Tuesday night that Syria’s use of chemical weapons presented a danger to American security and violated the world’s “sense of common humanity.” He pledged no American boots on the ground, but warned: “The United States military doesn’t do pinpricks.” Read more on NBC News

Syria's foreign minister: We'll declare chemical weapons, sign arms ban

The Syrian government Tuesday appeared poised to accept the Russian proposal for Syria to hand over chemical weapons amid a flurry of diplomatic maneuverings around the world. Foreign Minister Walid al-Moualem said Damascus was ready to cooperate on the Russian initiative and join a convention that forbids their use. Read more on NBC News

With new iPhones, Apple chose style over screen size

At an Apple press event in Cupertino, Calif., the company showed off the new iPhone 5S and 5C up close. While the flagship 5S does come with some engineering excellence, these phones on the whole play to Apple's core strength: Style. Read more on NBC News

Prison guards on paid leave after Cleveland kidnapper Castro’s suicide

Two prison guards on duty when Cleveland kidnapper Ariel Castro was found hanged in his cell were placed on paid leave Tuesday as investigators look into the suicide. Read more on NBC News

Cops trying to recover footage from Zimmerman iPad after dispute

George Zimmerman's wife used her iPad to record a confrontation with her estranged husband, and investigators are trying to recover the footage, Florida police said Tuesday. Read more on NBC News

Midwest bakes under heat dome

A surge of late-summer heat was blazing across the U.S. Midwest on Tuesday, prompting officials to shutter public schools in Illinois and Ohio as near-record high temperatures turned the region into a veritable oven. Read more on NBC News

Judge in YouTube confession case delays arraignment

An Ohio courtroom became a stage for legal theater Tuesday when the judge presiding over the arraignment of a confessed drunken driver expressed frustration at the glut of news reporters huddled behind the defendant and abruptly postponed the proceeding. Read more on NBC News

Congressional leaders honor victims of 1963 Birmingham church bombing

House and Senate leaders Tuesday formally awarded Congress’ highest civilian honor to the families of four girls killed in an Alabama church bombing nearly half a century ago that is now regarded as one of the most horrific acts of violence of the civil rights era. Read more on NBC News