* SABMiller, Nestle give weak updates
* FTSEurofirst 300 and Euro STOXX 50 slip
* Ukraine tensions also weigh
By Sudip Kar-Gupta
LONDON, April 15 (Reuters) - Weak updates from leading European companies weighed on the region's stock markets on Tuesday, and the threat of costly sanctions against Russia also capped appetite for equities.
The pan-European FTSEurofirst 300 index, which rose 16 percent in 2013 to post its best annual gain since 2009, slipped 0.2 percent to 1,317.14 points in early session trading.
The euro zone's blue-chip Euro STOXX 50 index retreated by 0.3 percent to 3,121.04 points.
European shares have rallied over the last year, helped by pledges from the European Central Bank (ECB) to support the economy in its recovery from the effects of the euro zone's sovereign debt crisis.
But this has also led stock market valuations higher, and many investors have said that companies now need to show a strong recovery in profits in order to keep the rally on track.
Graphic on MSCI Europe valuations:
On Tuesday, several firms posted downbeat business updates.
Brewing company SAB Miller fell 2 percent after a sales update that some analysts said failed to meet forecasts.
French cosmetics group L'Oreal and Nestle both undershot market expectations with first-quarter sales, though they forecast a return to top-line growth in coming quarters.
"So far, the results are coming in worse than expected. That's why the markets have been consolidating a little bit," said Clairinvest fund manager Ion-Marc Valahu.
Traders said worries over the situation in Ukraine could also weigh on stock markets in coming weeks.
European foreign ministers agreed to step up sanctions against Russia and U.S. officials said they were in consultations with European partners on how to punish Moscow following the seizure of government buildings in eastern Ukraine by pro-Russian separatists.
Europe bourses in 2014: link.reuters.com/pap87v
Asset performance in 2014: link.reuters.com/gap87v
Today's European research round-up (additional reporting by Francesco Canepa; Editing by John Stonestreet)