The number of people crossing the perilous Darien Gap linking Panama and Colombia has hit a record high of 400,000 in the year to September, official data showed, as migration to the United States intensified despite efforts to curb the flow.

More than half of those migrants were children and babies, Panama's security ministry said in a statement, adding that September alone saw the number of crossings increase by a fifth compared to the previous month.

The year-to-date figure of 402,300 migrants is almost double the number for the whole of 2022.

The United Nations had estimated in April that the number of migrants for the entire year would be 400,000.

Most of the migrants traversing the dangerous stretch of jungle are Venezuelans, with others from Ecuador, Haiti and other countries, Panama's security ministry has said.

Panama announced earlier this month measures to stop the increase in migration, including deporting more people with criminal records and a decrease in the number of days some tourists are allowed to stay in the country.

These measures follow a two-month program launched in April by the United States, Panama and Colombia to tackle undocumented immigration.

Costa Rica, another transit country for the migrants, declared a state of emergency earlier this week, and its President Rodrigo Chaves said he would visit the Darien Gap in early October in an effort to contain a migrant crisis.

The United States in May rolled out a new policy to deter illegal crossings, including deporting migrants and banning re-entry for five years, as the Biden administration grappled with migration at record highs.

The tougher measures drove the border-crossing rate down some 70% initially, but the number of migrants arriving at the U.S. border with Mexico has surged recently, suggesting the early deterrent effect is wearing off.

Some African and Cuban migrants and asylum seekers heading to the United States told Reuters they were flying into Nicaragua to bypass the perils of the Darien Gap.