US Secretary of Defense Robert Gates (l.) and Secretary of State Hillary Clinton look through binoculars toward North Korea during a visit to observation post Ouellette at the Demilitarized Zone on Wednesday in Panmunjon, South Korea. Mark Wilson/AP
United States Marine Sgt. Adam Wilson from Bravo Company of the 1st Battalion of the 2nd Marines mans a Mark 19 heavy gun at a fire position near Musa Qaleh, in northern Helmand Province, southern Afghanistan, on Wednesday. Kevin Frayer/AP
A polar bear has a bucket on his head, while a cub swims nearby in the cooling waters of Moscow Zoo on Wednesday as a heat wave continued in central Russia. Misha Japaridze/AP
British Prime Minister David Cameron (c.) eats a hotdog with New York City Mayor Michael Bloomberg on Wednesday during his first visit to the US since taking office. Bebeto Matthews/AP
Girls practice with air rifles during a weapons training course as part of an eight-day training program organized by the Bajrang Dal, a Hindu group, inside a school premises on the outskirts of Jammu, India, on Wednesday. One hundred and fifty girls participated in the program which aims to equip them with self defense skills. Mukesh Gupta/Reuters
Trinamool Congress supporters sit on a road as they attend a rally marking Martyr's Day, in Calcutta, India, on Wednesday. The day commemorates 13 Youth Congress workers who were killed by police in 1993. Bikas Das/AP
This image provided by the European Southern Observatory shows a new near-infrared image of the R136 cluster of stars. At birth, the three brightest stars each weighed more than 150 times the mass of the sun. The most massive star, known as R136a1 and located at the center of the image, has been found to have a current mass of 265 times that of the sun. It also has the highest luminosity, close to 10 million times greater than the sun. CJ Evans/P. Crowther/ESO/AP
The mascot dog of Target stores is led around the floor of the floor of the New York Stock Exchange prior to opening bell ceremonies, on Wednesday in New York. Target's mascot was there to mark the opening of the company's first store in Manhattan. Richard Drew/AP
A model displays a creation by Indian designer Rohit Bal at the Pearls Delhi Couture Week 2010 in New Delhi, India, on Wednesday. Mustafa Quraishi/AP
One of the two leopard cubs Pati and Jaya looks out from an enclosure at the Jardin des Plantes menagerie in Paris on Wednesday. The two cubs were born two months ago in Paris, the Museum National d'Histoire Naturelle said. Gonzalo Fuentes/Reuters
Obama phoned Russia's Vladimir Putin Thursday to discuss a US proposal for resolving the Ukraine crisis. Earlier, the US moved to begin a regimen of sanctions against Russia. Will those be enough to prevent Russia's annexation of Crimea?
[Updated 9:30 p.m. ET] President Obama appealed to Russian President Vladimir Putin late Thursday, during a personal phone call, to agree to direct talks with Ukraine aimed at resolving, through diplomacy rather than military confrontation, Russia's concerns about the future direction of the Ukrainian government and of the rights of ethnic Russians living in Ukraine.