* Investors cautious after sanctions talks
* Samsung Elec rises on new smartphone release
SEOUL, March 27 (Reuters) - Seoul shares inched higher on early Thursday, supported by a rise in market heavyweight Samsung Electronics while investors cautiously weighed the agreement between the United States and the European Union to cooperate on tougher economic sanctions against Russia.
The Korea Composite Stock Price Index (KOSPI) was up 0.2 percent at 1,967.51 points as of 0210 GMT.
"As in Wall Street, the sanctions on Russia are used as an excuse for investors taking a breather following yesterday's sharp rebound," said Chung Seung-jae, an analyst at Mirae Asset Securities.
The KOSPI rose 1.2 percent on Wednesday, notching its biggest one-day gain in more than a month.
The U.S. and the EU on Wednesday agreed to work together to prepare possible tougher economic sanctions in response to Russia's behaviour in Ukraine. The geopolitical concerns brought down Wall Street, reversing earlier gains.
However Samsung Electronics Co Ltd, the biggest component in KOSPI, underpinned the market.
Samsung Electronics gained 3 percent after South Korea's top mobile carrier SK Telecom Co Ltd brought forward the launch of the company's newest flagship smartphone to Thursday, in a bid to cushion the blow from a sales suspension. SK Telecom shares rose 1.4 percent.
Meanwhile, bucking the trend were Naver Corp and Hotel Shilla Co Ltd, which dropped 3.8 percent and 2.8 percent, respectively.
Offshore investors net purchased 79 billion won ($73.5 million) worth of KOSPI shares near mid-session, while institutional and retail investors positioned as net sellers.
The KOSPI 200 benchmark of core stocks was up 0.2 percent, while the junior KOSDAQ edged 0.4 percent lower. ($1 = 1074.9500 Korean Won) (Reporting by Jungmin Jang; Editing by Eric Meijer)