WASHINGTON - Presumptive U.S. Democratic presidential nominee Barack Obama announced Friday that he and former rival Hillary Clinton would campaign together on June 27 for the first time. But no details were offered, such as where this might happen, for how long, whether it will be multiple events and days. The two politians are to meet in Washington on June 26 to soothe the tensions between Obama and some Hillary supporters. Obama, an African-American who is a first-term U.S. Senator from Illinois, beat Mrs. Clinton, a Senator from New York and a former first lady to clinch the Democratic presidential nomination on June 3. However, Hillary Clinton waited until four days later to concede the race to Obama. Some Democrats are pushing for a joint Obama-Clinton ticket in the general election to unite the party.Meanwhile, Obama leads Republican John McCain by 48 per cent-42 per cent among registered voters in the survey, taken Sunday through Thursday, a new USA TODAY/Gallup Poll shows. In a survey taken May 30 to June 1, Obama held a three-point lead over the Arizona senator. Among likely voters, Obama led McCain by 50 per cent-44 per cent, an insignificant change from his earlier standing of 49 per cent-44 per cent. Obama claimed the nomination on June 3, when primaries in Montana and South Dakota gave him a majority of delegates to the Democratic National Convention, meeting in August. The survey of 1,625 adults - including 1,460 registered voters and 1,310 likely voters - has a margin of error of +/- 3 percentage points. Among independents - the group that usually determines election outcomes - Obama leads 48 per cent-36 per cent. The poll shows sharp divisions between the two candidates' support along lines of sex, race and age: Women support Obama by 14 points while men back McCain by 3 points. Whites support McCain by 6 points while blacks almost unanimously back Obama, who is the first African-American to claim a major party's presidential nomination. Of 130 blacks surveyed, 129 support the Illinois senator. Young people back Obama while seniors support McCain. Among those 18 to 29 years old, Obama holds a better than 2-1 edge. Among those 65 and older, McCain leads, 49 per cent-40 per cent.There were significant regional differences as well. McCain leads in the South, Obama on both the East and West coasts. In the battleground Midwest, Obama is ahead 48 per cent-40 per cent.