Senegal's sovereign credit rating was cut by S&P Global to B- late on Monday and immediately put on a negative outlook - effectively another downgrade warning - due to growing concerns about the country's soaring debt levels.

Senegal recently increased its debt figures following an audit and S&P said it now estimated that the government's debt-to-GDP ratio finished last year at 118%, compared to its previous forecast of 104%.

Senegal's finance ministry issued a statement saying it "took note" of S&P's decision and wanted to "reaffirm its commitment to budget transparency, and to reassure all its partners of the state's ability to meet its commitments."

S&P said the decision to put Senegal's rating on 'negative outlook' following the one-notch downgrade reflected concerns that the higher debt, coupled with higher-than-expected financing requirements for this year and large debt payments next year, would "intensify funding pressures on the government".

"We understand that Senegal's external financing requirements materially exceed our previous estimates, which may complicate negotiations on a new programme with the International Monetary Fund (IMF)," S&P added in its rating review published late on Monday.

The finance ministry said talks with the IMF were continuing "proactively and constructively" with the aim of holding an IMF Board meeting on the misreporting of its debt levels "as soon as possible".

Senegal's sovereign bonds rose in international trading on Tuesday, although they have lost roughly a quarter on their value since the misreporting was first revealed in September last year.

S&P added that Senegal's 118% debt-to-GDP ratio was the highest of all the African countries it rates in the 'B' long-term rating bracket. Its next rating review date is scheduled for November 16.

"This significant upward revision (in debt) leaves Senegal with no fiscal space for a cushion against any potential economic or financial shock in the future," the rating agency said.