The broad-based S&P 500 rose 0.2 percent to 2,502.65, while the tech-rich Nasdaq Composite Index climbed 0.4 percent to 6,398.81.
Both New York Federal Reserve Bank President William Dudley and Chicago Fed President Charles Evans said they believe the USA economy's fundamentals are sound, and both said they support gradual rate hikes ahead.
Yellen's remarks attempt to resolve a debate that has split members of the central bank among those anxious that inflation may be permanently anchored below the Fed's 2 percent target because of structural changes in the global economy, and those who feel it is only a matter of time before tight labor markets lead wages and prices to rise.
The dollar index was up 0.04% to 93.07 as of 04:22 BST. The yen pared some of the previous day's gains, which followed North Korea's declaration it could shoot down USA warplanes. The much-anticipated tax reform package is expected to be presented during a speech in Indianapolis, at 3 p.m. ET. With President Trump due to reveal tax reform plans, the rally may extend to the next resistance at the 94 level.
Banks put in a solid performance amid expectations of higher interest rates, with Standard Chartered, Lloyds and RBS among the top gainers, although StanChart was also boosted by an upgrade to "hold" from "sell" at Investec.
Advertisment Greater China markets bucked declines in most Asian markets to post slight gains on Wednesday as investors digested Federal Reserve Chair Janet Yellen's overnight speech and as North Korea tensions took a backseat. President Donald Trump has not said whether he plans to re-appoint Yellen or overhaul the central bank's seven-member board of governors.
Gold is highly sensitive to rising USA interest rates, as they increase the opportunity cost of holding non-yielding bullion versus the dollar. But even with uncertainty about the possible reasons for the low rate of inflation - from misjudging the strength of the labor market to the impact of foreign competition on the global supply chain - Yellen said the Fed "should be wary of moving too gradually".
Egyptian woman, who was world's heaviest, dies in UAE hospital
Following the procedure , which was paid for through a crowdsourcing campaign, she managed to reduce her weight to just 176kg. But after her family fell out with docs at Saifee hospital in May, she was later flown to Abu Dhabi's Burjeel hospital .
Iraq's major Shiite Party opposed to Kurdish referendum
He said the move is opposed by Turkey, Iran and the Syrian government, but said "the will of the people will prevail in the end". Akar and al-Ghanimi emphasized the importance of cooperation in the fight against PKK and Daesh, the statement said.
Wade to AP: Weighing options after agreeing to Bulls' buyout
The Thunder, who acquired Carmelo Anthony in a blockbuster trade over the weekend, would only be able to offer the minimum salary. Talks between the two sides about a resolution intensified ahead of Monday's start of training camp, according to ESPN .