SAN ANTONIO, Texas -- White House hopeful Barack Obama shrugged off two defeats in Tuesday's nominating contests, saying he was on his way to winning the Democratic Party's presidential nomination.

Earlier his bitter rival Hillary Clinton won closely fought races in Ohio and Rhode Island, while Obama took Vermont.

But the race was still too close to call in the biggest prize of Texas, as the two candidates seek to lock down the 2,025 candidates needed to secure the party's ticket to run in the November elections.

"No matter what happens tonight, we have nearly the same delegate lead as we did this morning, and we are on our way to winning this nomination," Obama told cheering supporters.