Germany's Germanischer Lloyd (GL) has become the third European classification society to stop assessing Iranian vessels.
The group wrote to US pressure group United Against Nuclear Iran (UANI) on15 June to reveal the move, Reuters said.
It said it had stopped offering services to boxship company Islamic Republic of Iran Shipping Lines (IRISL) and tanker owner NITC.
"It is of the utmost importance that we maintain our good reputation," GL said in the letter.
"Therefore
