* Yellen's speech at 12:45 p.m. ET
* Apple, Facebook up 1 pct premarket
* Nvidia up on AI announcement
* Futures: Dow down 1 pt, S&P off 1.5 pts, Nasdaq up 12.75 pts (Adds details, comment, updates prices)
Sept 26 (Reuters) - A recovery in technology stocks looked set to lift the Nasdaq on Tuesday, but tensions between the United States and North Korea could weigh on the S&P and the Dow.
Apple and Facebook were up about 1 percent in premarket trading. Technology stocks had dropped sharply on Monday on increasing worries that the top-performing sector was falling out of favor.
Investors are also looking for more clarity on an interest rate hike this year from Fed Chair Janet Yellen's speech at an annual meeting of National Association for Business Economics.
"The indices are pointing to a lower opening as the geopolitical 'Fear Factor' weighs, causing institutions to rethink allocations as the last days of the quarter approaches," said Peter Cardillo, chief market economist at First Standard Financial in New York.
North Korea appears to have boosted defenses on its east coast, according to a South Korean lawmaker, after Pyongyang said President Donald Trump had declared war and that it would shoot down U.S. bombers flying near the peninsula.
At 8:30 a.m. ET, Dow e-minis were down 1 points, or 0 percent, with 25,271 contracts changing hands.
S&P 500 e-minis were down 1.5 points, or 0.06 percent, with 148,538 contracts traded.
Nasdaq 100 e-minis were up 12.75 points, or 0.22 percent, on volume of 34,417 contracts.
Red Hat rose 4.1 percent after the Linux distributor's quarterly profit came in above estimates and the company raised its full-year forecast.
Nvidia was up 2.8 percent after launching an artificial intelligence inference software.
Economic data includes a report on new U.S. single-family home sales, which is likely to show an increase in August after unexpectedly falling in July. The report is expected at 10:00 a.m. ET.
Also scheduled for release at 10:00 a.m. ET is a report on U.S. consumer confidence, which is expected to show it fell to 120 in September from 122.9 in August.
Cleveland Fed Chief Loretta Mester, her Atlanta counterpart, Raphael Bostic, and Fed's Board Governor Lael Brainard are also scheduled to speak later in the day. (Reporting by Sruthi Shankar in Bengaluru; Editing by Anil D'Silva)