Sept 24 (Reuters) - Argentine assets roared ahead for a

third consecutive day on Wednesday after the U.S. floated a $20

billion swap line to support the country's struggling markets,

while most other Latin American currencies weakened against a

firm dollar.

In a post on X, U.S. Treasury Secretary Scott Bessent

disclosed ongoing negotiations for a $20 billion swap line with

Argentina's central bank, while also revealing the United

States' willingness to purchase secondary or primary government

debt.

The remarks followed Argentine President Javier Milei's

meeting on Tuesday with U.S. President Donald Trump, who voiced

support for the country and added that a financial bailout was

not needed.

Additionally, the World Bank pledged to deploy $4 billion in

the coming months to back the South American nation's reform

agenda.

Argentina's international bonds rallied, with a 2029 note

jumping 4.7 cents on the dollar.

INVESTORS 'MORE COMFORTABLE' WITH US SUPPORT

Its peso currency continued to climb, gaining

0.3% and recovering losses suffered after Milei's legislative

setback on September 7, which sparked the selloff and even

prompted an intervention last week by the central bank.

"There are several angles to this, but the 20 billion itself

is a high number. So people are definitely more comfortable with

the U.S. support, and that number is enough for it to be a

meaningful circuit-breaker in terms of the kind of vicious

spiral that you were seeing," said Thomas Haugaard, portfolio

manager of EM debt at Janus Henderson ( JHG ).

Stocks in Buenos Aires also built on the rally,

soaring 3.8% to take their gains over three days to near 12%.

In broader Latin America, the currencies index

lost 0.3%, with a stronger U.S. dollar weighing

on the regional currencies after Federal Reserve Chair Jerome

Powell struck a cautious tone on further policy easing.

The Brazilian real fell 0.6% against the dollar. Sao

Paulo's main stock index was largely flat, though at a

record level. Fresh data showed a jump in Brazilian consumer

confidence to its highest level since the end of last year.

Meanwhile, MSCI's gauge of the region's equities

also slipped about 0.2%.

Mexican equities flattened and the local peso

fell 0.4% after headline inflation accelerated in the first half

of September to near the upper limit of the central bank's

target.

The data precedes the central bank's interest rate decision

due on Thursday. Economists expect a moderate rate cut as the

central bank continues its battle against weak economic

conditions.

If delivered, that would be the 11th quarter-point reduction

since the start of 2024.

The Colombian peso lost 0.5%, while stocks

rose 0.65% to surpass a 12-year peak.

Colombia is also gearing up for a rate decision. The central

bank is expected to hold rates next week and extend that trend

for the rest of the year.

Chile's peso fell 0.7%, while its main stock index

rose 0.5%. Peruvian stocks were a

standout, up 2.2% to hit an all-time high.

Elsewhere, the Czech National Bank left interest rates

unchanged for the third time in a row and voiced the need for a

relatively tight policy amid looming inflation risks.

The currency crown fell 0.3% - eyeing its worst

day in more than a month.

Key Latin American stock indexes and currencies:

Stock indexes Latest Daily % change

MSCI Emerging Markets 1350.99 0.33

MSCI LatAm 2554.96 -0.16

Brazil Bovespa 146294.47 -0.09

Mexico IPC 62356.28 -0.01

Chile IPSA 9194.76 0.53

Argentina MerVal 1884969.05 3.83

Colombia COLCAP 1883.6 0.65

Currencies Latest Daily % change

Brazil real 5.3147 -0.61

Mexico peso 18.4128 -0.38

Chile peso 955.21 -0.71

Colombia peso 3871.95 -0.47

Peru sol 3.5091 -0.32

Argentina peso (interbank) 1,365.0 0.29

Argentina peso (parallel) 1,370.0 2.84