A Chinese container ship has hit a wall of the recently-widened Panama Canal, amid concerns that it has less space for manoeuvres and could be unsafe.
It is the third accident of this kind since the multi-million dollar expansion opened a month ago.
Workers groups say the new locks are too small for safe operations now that the canal can take ships three times larger than before.
The Panama Canal authority says it is investigating the incidents.
The Xin Fei Zhou, owned by China Shipping Container Lines, suffered a large gash in its hull and is now undergoing repairs.
The new locks are designed for ships to use tugboats to guide them through the canal.
In the old canal locomotives (known as "mules") would keep the ships correctly aligned as they passed through.
A study for the International Transport Workers' Federation released earlier this year concluded that the new lock chambers were too small for the tugboats to be able to manoeuvre properly.
Work on the expansion began in September 2007 and was originally planned to finish in 2014.
Following delays caused by construction workers' strikes and disputes over cost overruns, the date for completion was pushed back to April 2016.
The first voyage through the new expanded canal was on 26 June.