Maritime intelligence agency Lloyd’s List reported that ship movement through the Strait of Hormuz has once again come to a stop following the U.S. President’s announcement of a blockade plan. The report said vessels navigating the vital Middle Eastern waterway either halted or turned back immediately after the declaration. Until Sunday, limited traffic, including oil tankers, had continued despite risks in the area.

According to Lloyd’s List, ship movement had slightly increased on Saturday as some shipping companies attempted to move their vessels out of the Gulf region amid hopes of a possible ceasefire. However, the U.S. blockade announcement dramatically changed the situation, leading to a complete halt in maritime activity. At least two ships that were leaving the strait reportedly turned back.

The report warned that the disruption in one of the world’s most critical maritime routes could have significant consequences for global energy markets and trade.