Security noticeably tighter around Obama's house

Barack Obama is back home in Chicago after last week's Democratic National Convention and security around his South Side home has been tightened.

Lines of concrete and metal barriers are blocking access to a one-block stretch of Greenwood Avenue, where Obama lives. Security was tightened after he officially became the Democratic party's nominee for president.

Both ends of Obama's street are blocked off and are being guarded by police and Secret Service agents.