(Reuters) - The number of vessels that passed through the Panama Canal, the world's second busiest waterway, fell to an average of 32.6 per day for a total of 1,011 ships in January, the first month-on-month decline in almost a year, according to a bulletin published on Tuesday by the canal's administrating authority.

Following a severe drought between late 2023 and early 2024 that forced passage restrictions, the canal saw a solid increase in transits during 2024 to a total of 1,059 ships in December, according to statistics by the Panama Canal Authority.

But the demand recovery was not enough to fill the 36 passage slots that remained on offer since September, the data showed, amid toll increases that led to some shippers opting for longer routes to Asia.

In February last year, the total number of transits fell to 662 ships from 702 in January. But from February on, traffic increased almost 60% through the end of the year.

U.S. Secretary of State Marco Rubio earlier this month visited Panama City and met the canal's top officials to discuss tolls and the presence of Chinese businesses near the waterway, which some Washington politicians and government officials have identified as a security risk for its operation.

In the fiscal year that ended in September, the canal reported a 5% fall in toll revenue to $3.18 billion amid the drought. In the fiscal years ended between 2020 and 2023, the canal's toll revenue had increased almost 26% to $3.35 billion, according to the canal's annual reports.

Following Rubio's visit, the U.S. and Panama governments had a public dispute over tolls to be paid by U.S. military vessels, which have priority of passage through the canal, according to a 1977 neutrality treaty signed when the U.S. agreed to return the canal to Panama.

Panama's president, Jose Mulino, said Washington was spreading "lies and falsehoods" when it claimed that U.S. government vessels would be able to pass through the canal without paying.

The comments exacerbated tensions between the two countries after the U.S. had cited progress on military cooperation and strategies on China's expansion in Panama.