Updates with mid-session trading

By Lisa Pauline Mattackal and Purvi Agarwal

Feb 28 (Reuters) - Most emerging market currencies and stocks tumbled on Friday, as investors remained cautious ahead of a March 4 tariff deadline on top U.S. trading partners, while assessing the impact of a U.S.-Ukraine meeting that ended in disaster.

U.S. President Donald Trump reiterated that 25% duties on imports from Canada and Mexico will come into effect on Tuesday, after raising hopes of further delay on Wednesday.

MSCI's gauge of Latin American currencies .MILA00000CUS fell 0.9% on the day, set for its first weekly loss in eight. The dollar was supported by a broadly in-line U.S. inflation reading.

Mexico's peso MXN edged down 0.2%. It was on track to slip 0.5% for the week, but eyed a 0.7% gain for the month.

"Even though tariff talk has been confusing, it seems like there is intention behind what the administration is doing in trying to get more concessions," said Juan Perez, director of trading at Monex.

Meanwhile, U.S. President Donald Trump's meeting with his Ukrainian counterpart ended in disaster, after they traded verbal blows at the White House over the war with Russia. Ukrainian President Volodymyr Zelenskiy was visiting Washington to sign a critical minerals deal between the countries.

Russia's rouble RUB= fell 1.9% against the dollar, but was set for its fourth week of gains.

Ukraine's dollar bonds were little changed after the meeting. Most were lower on the day, but had recouped some declines logged earlier in the session.

Most maturities, however, were on track to rise for the month, on optimism around a peace deal between Russia and Ukraine earlier in the month.

"They are not including European and Ukrainian leadership (in peace talks), so there is going to be friction, which is not what markets wanted. They wanted to closeout the week with some sort of positive press conference," said Perez.

"What this really means for EMs is that you have to be very cautious."

Back in LatAm, the Brazilian real BRL= and the Chilean peso CLP= fell 0.8% and 1.2% respectively.

All regional stock indexes were in the red, with Argentina's Merval .MERV the only outlier with a 0.6% gain. The index of regional stocks .MILA00000PUS dropped 1.8%, set for its worst week since October 2023.

Despite tariff headlines and geopolitical developments keeping trading in EMs volatile, most LatAm currencies have strengthened against the dollar this year on hopes of the threatened tariffs largely being a negotiating tactic.

EM equities have seen $5.1 billion in outflows over the past four weeks, according to data from Bank of America Global Research. EM debt has seen two straight weeks of net inflows.

The overall EM stocks index .MSCIEF is set to fall 2%, and the currency index .MIEM00000CUS was on track to drop 0.3% on a weekly basis.

HIGHLIGHTS

** Brazil, Eletrobras reach deal over voting power, nuclear plant

** Brazil's finance minister isolated as market fears of a leftist pivot mount

** Romanian government survives no-confidence vote

Key Latin American stock indexes and currencies at 2025 GMT:

(Reporting by Lisa Mattackal and Purvi Agarwal in Bengaluru; Editing by Nia Williams and Nick Zieminski)

((LisaPauline.Mattackal@thomsonreuters.com;))