* U.S. budget debate, Middle East risks hit stocks
* Construction firms among biggest losers
* Seoul Pharma rallies on media report of Pfizer deal
SEOUL, Nov 15 (Reuters) - Seoul shares skidded to their lowest intraday levels in more than three months on Thursday, as Middle East violence soured sentiment already hurt by concerns about U.S. budget woes.
Foreigners continued to offload South Korean stocks for a sixth consecutive session.
The Korea Composite Stock Price Index (KOSPI) lost 1.35 percent to 1,868.44 points as of 0225 GMT.
“Investors are dumping stocks, doubting whether the U.S. will be able to quickly resolve a looming fiscal crisis. Corporate earnings outlooks have been also downgraded, weighing on the market,” said Lee Seon-yeob, an analyst at Shinhan Investment.
“Investors see little reason to buy stocks and fear that the KOSPI may fall further,” he said.
U.S. President Barack Obama set up a drawn-out fight over the fiscal cliff when he stuck to his pledge to raise taxes on the wealthy as the first step in a budget deal that would prevent the U.S. economy from slipping into a recession.
In the Middle East, Israel launched a major offensive against Palestinian militants in Gaza on Wednesday, killing the military commander of Hamas in an air strike.
Most sectors lost ground, with construction firms among the biggest losers. Samsung Engineering fell 5.3 percent, while Daewoo Engineering & Construction lost 2.3 percent.
Large stocks also fell, with Samsung Electronics down 2.1 percent and Hyundai Motor losing 2.1 percent.
Among small-cap stocks, Seoul Pharma Co Ltd bucked the trend and soared as much as 15 percent after a media report said that the pharmaceutical company was in talks with Pfizer Inc to have its erectile dysfunction drug branded as Viagra in South Korea.
Seoul Pharma and the South Korean unit of Pfizer said nothing has been decided. (Reporting by Hyunjoo Jin; Editing by Richard Borsuk)