RIO DE JANEIRO, Feb 23 (Reuters) - Latin American currencies weakened on Monday on fears that U.S. Federal Reserve Chair Janet Yellen may signal in congressional testimony on Tuesday that interest rates could go higher by June despite a recent slew of weak economic data.

Greece, another major constraint on global appetite for risk, also weighed on investor sentiment as Athens missed a deadline on Monday to present reform plans that are needed to seal a euro zone financial lifeline.

"Until Greece secures the deal, markets will remain heavy," said Luciano Rostagno, chief strategist at Mizuho Bank in Brazil.

Prospects for higher U.S. interest rates and fears that Greece may be forced to leave the euro zone have been among the main drags on emerging markets recently as they reduce investors' appetite for risk.

The Colombian peso led regional losses, falling 1.6 percent. The Chilean peso slid 1.1 percent as it was also weighed on by a drop in prices for copper, the country's main export product.

The Brazilian real dropped 0.4 percent to 2.8773 to the dollar after earlier sliding past 2.9 per dollar for the first time in more than 10 years.

Latin American stock markets were steady, however, with Brazil's benchmark Bovespa index up 0.1 percent.

Supporting the Brazilian market were shares of education companies such as Kroton Educacional SA, which jumped 6 percent after the government clarified new rules for a student loan program that had been considered detrimental to education companies.

Key Latin American currencies and stock indexes at 1845 GMT Stock indexes daily % YTD % change change Latest MSCI Emerging 982.26 -0.22 2.94 Markets MSCI LatAm 2630.21 0.1 -3.67 Brazil Bovespa 51295.09 0.11 2.57 Mexico IPC 43572.38 0.05 0.99 Chile IPSA 4034.64 1.01 4.77 Chile IGPA 19600.26 0.87 3.87 Argentina MerVal 9482.569 0.48 10.53 Colombia IGBC 10525.35 0.38 -9.53 Peru IGRA 13638.54 -0.95 -7.81 Venezuela IBC 3481.78 1.95 -9.77 Currencies daily % YTD % change change Latest Brazil real 2.8773 -0.44 -7.64 Mexico peso 15.043 -0.15 -1.99 Chile peso 622.5 -1.12 -2.59 Colombia peso 2498.26 -1.58 -4.41 Peru sol 3.091 -0.29 -3.62 Argentina peso 8.7075 -0.06 -1.81 (interbank) Argentina peso 13.12 -0.38 6.71 (parallel) (Reporting by Walter Brandimarte in Rio de Janeiro and Bruno Federowski in Sao Paulo; Editing by Peter Galloway)