. >> and erroll burnett. coming in this hour. tough new sanctions against russia. >> a choice that russia and president putin in particular has made. >> why some now believe that russia hasn't been more isolated since the end of the cold war. also ahead. >> well the area around here seems to be completely abandoned. right now amid all the destruction there doesn't seem knob any signs of life. >> a rare look inside gaza, a city devastated by weeks of the israeli air strikes. >>> you heard a brief clip. u.s. president barak obama says it's not a new cold war but a effort to make russia realize that ukraine has the right to determine its own future. >> and they have announced the toughest sanctions yet on russia, punishment for its support of rebel forces in eastern ukraine. white house correspondent reports. >> reporter: the u.s. with europe ratchets up the pressure on russia. >> the united states is imposing new sanctions in key sectors of the russian economy, energy arms and finance. we're blocking the exports of the specific goo