South Korean stocks ended lower Monday, snapping their three-day winning streak, weighed down by uncertainty over the Ukraine-Russia conflict and worries over the US monetary policy. The Korean won fell against the US dollar.

The benchmark Korea Composite Stock Price Index (Kospi) retreated 20.97 points, or 0.77 percent, to close at 2,686.05 points.

Trading volume was moderate at about 495 million shares worth some 8.6 trillion won ($7.1 billion), with gainers outnumbering losers 454 to 394.

Institutions sold a net 331 billion won and foreigners offloaded 486 billion won, while retail investors bought 798 billion won.

The market opened higher but soon turned south as investors took a wait-and-see mode following a three-day gain that stemmed from hopes of progress in the Ukraine-Russia peace talks.

"Investors seem to be growing impatient as the Ukraine-Russia peace talks have not shown concrete results over the weekend," Kiwoom Securities analyst Kim Se-heon said.

"The hawkish stance of the US Federal Reserve also seems to have increased short-term profit-taking among investors," he added.

Earlier, a high-ranking Fed official made hawkish remarks on borrowing costs, saying that it is necessary to raise the interest rate by 50 basis points at least once this year.

US Fed Chair Jerome Powell, who had been backing multiple rate hikes to rein in mounting inflation pressure, is slated to speak on Monday in US time.

Most large caps closed lower in Seoul.

Market bellwether Samsung Electronics lost 1.13 percent to 69,900 won, and No. 2 chipmaker SK hynix retreated 1.61 percent 122,000 won.

Internet portal operator Naver shed 1.6 percent to 339,000 won, with its rival Kakao dipping 3.23 percent to 105,000 won

Among gainers, bio heavyweight Samsung Biologics edged up 0.12 percent to 829,000 won, and battery maker LG Energy Solution added 1.05 percent to 386,000 won.

The local currency closed at 1,216.3 won against the US dollar, down 8.7 won from the previous session's close. (Yonhap)