Among Republicans, John McCain further consolidated his unassailable lead with a similar show in the three primaries.

"Tonight we're on our way," Obama told cheering supporters in Wisconsin after adding Virginia, Maryland and Washington DC to his kitty. "But we know how much further we have to go on," said the beaming Illinois senator.

Obama now has 1,212 delegates compared to 1,191 of Clinton who is now virtually facing a do-or-die battle in the March 4 contests in delegate-rich states of Ohio and Texas.

A minimum of 2,025 delegates are required to win the nomination at the Democratic Party convention in August.

Clinton's deputy campaign manager Mike Henry announced his resignation, two days after campaign manager Patti Solis Doyle was sacked, adding to the impression that panic was setting in.

Obama, 46 who is bidding to be the first African American to be elected to the Oval office has won eight consecutive contests after the 'Super Tuesday' draw.

A first time senator, he was heavily favoured to win the contests in the yesterday's so called "Potomac primaries", where blacks account for a big proportion of voters.

However, exit polls suggest that he split the white vote with Clinton, clearly building on the momentum which could further compound problems for the former first lady.

But a defiant Clinton maintained she was still leading.

Source: DDNEWS