What exactly is the US saying it is blocking?

After the US and Iran failed to reach a peace deal in Pakistan, Donald Trump said the US would start "BLOCKADING any and all Ships trying to enter, or leave, the Strait of Hormuz". The US Central Command (Centcom) later said its forces would enforce the blockade "impartially" on vessels leaving and entering Iranian ports, including those in the Gulf and Gulf of Oman. However, Centcom also said US forces would not impede the freedom of vessels transiting to and from non-Irania