"Attempts by the enemy to reduce Iran's oil exports and capture the country's ships have taken place many times" in past months, Oil Minister Jawad Owji told Iran newspaper.
"When the enemy saw that it was helpless and could not stop our exports and contracts, it went for our ships," he said.
Owji’s comments came after US court documents showed the United States had seized the cargo of two tankers carrying Iranian crude.
Court documents that have been made public showed US authorities seized several weeks ago 700,000 barrels of oil which they said had left Iran in 2020 before being transferred to other vessels to avoid detection, AFP wrote.
The United States had previously issued a number of warrants to seize the cargo of tankers carrying Iranian oil to different countries.
It claimed in August 2020 the seizure of fuel aboard four tankers sent by Iran to Venezuela.
"Now you have heard one or two cases, but several other similar cases have occurred, which fortunately were thwarted by the good strength of the Armed Forces," Owji said.
The minister did not elaborate, but cited an announcement by Iran's Islamic Revolution Guards Corps that they had stopped an attempt by the US navy to seize a tanker carrying Iranian oil in the Sea of Oman in October.
"Iran's oil exports have risen under the toughest sanctions," said Owji.
The increase was thanks to "different methods used to win contracts and finding different buyers," Owji said.
"Both the Americans and the countries that have subjected us to oppressive sanctions have now come to the conclusion that these sanctions will eventually become ineffective and that their intention to reduce exports to zero will not be possible," he added.
The rise had "even increased the bargaining power of friends in Vienna," he said, in reference to Iran’s talks with world powers in the Austrian capital aimed at reviving the 2015 nuclear deal or the JCPOA.
Iran’s oil exports dropped from 2.5 million bpd after former US president Donald Trump exited the JCPOA in 2018 and reimposed sanctions.
However, its oil exports have risen to more than one million barrels per day (bpd) for the first time in almost three years, based on estimates from companies that track the flows, reflecting increased shipments to China, Reuters wrote.
Iran further increased exports in 2021 despite the sanctions, according to estimates from oil industry consultants and analysts.