According to sources, the two vessels are no longer listed as 'under Sheriff's arrest'. Specifically, on the ships seems to have been released, while the other one is still at port.
What is more, the arrests seem to target the vessels' owner, as other ships involved in Iranian trade sailed through the Singapore strait, without being arrested.
However, some LPG carriers loading from Iran turn off their AIS, in order to stay 'under the radar', as well as presenting misleading destinations to cover their tracks.
In November 2018, the US government issued Significant Reduction Exemptions (SREs) waivers to eight countries that were committed to decreasing the purchase of Iranian oil; China, India, Italy, Greece, Japan, South Korea, Taiwan and Turkey.
The SREs were granted for 180 days and expired on May 2, 2019.
After their expiry, the government of the US announced that the SREs will not be renewed, which is amongst their policies on bringing maximum pressure to bear against Iran, in order to negatively affect Iranian oil exports and bring them to zero.
Moreover, on May 20, Brian Hook - the US Special Representative for Iran - warned that the US will sanction any country that buys oil from Iran. This includes the purchase of oil by the eight countries that were previously granted SREs.