WASHINGTON — President Barack Obama has grabbed a significant lead over Mitt Romney in Ohio and holds a slender edge in Florida, according to two new polls by The Washington Post, indicating that there are fresh hurdles in the way of the Republican challenger’s best route to victory in the Electoral College.

Among likely voters, Obama is ahead of Romney in Ohio 52 percent to 44 percent. In Florida, the president leads 51 percent to 47 percent, a numerical but not statistically significant edge. Among all registered Florida voters, Obama is ahead by nine percentage points.

The new numbers come one week after a Washington Post poll in Virginia showed Obama with a clear lead there. More than half of all money spent in the campaign has focused on these three states, and many analysts say Romney has to win two of the three to capture the White House.

The GOP nominee’s advisers vowed to hit the reset button this week. But with the first debate scheduled Oct. 3, Romney is under new pressure to get his campaign refocused. The new polls add to the evidence that Obama has benefited most from the two parties’ conventions, a series of sharp, long-distance exchanges and a barrage of television ads.