Colombian navy divers are searching the Orinoco river for 10 people who disappeared on Tuesday after their boats capsized in the Orinoco river, which divides Colombia from Venezuela.
A total of 18 people were on board the boats, eight of whom were rescued.
Witnesses said one of the boats had a mechanical problem and was being towed by the other one when they hit a rock about 30m (100ft) from the shore.
The accident happened 10km (6.2 miles) downstream from Puerto Carreño.
A local government official, Diego Zárate, said of the eight people rescued two were Colombians and six Venezuelans.
Among the missing are thought to be a number of children.
Witnesses said the boat with mechanical problems was transporting watermelons while the one that came to its rescue was carrying passengers.
But a Colombian navy official said he did not know what the two vessels were doing navigating the fast-flowing river in the early hours of Tuesday when it was still dark.
A search of the riverbanks has so far yielded no result.