European Union sources said a new sanctions round will include measures against North Korean cargo ships carrying military equipment to Russia.
The European Commission is also expected to propose sanctions on tankers that are ignoring the G7 oil price cap on Russian crude shipments, Reuters reported.
The EC is drawing up its 14th set of measures to target the Putin regime over the Ukraine war.
Western nations have claimed North Korea is supplying weapons including ballistic missiles and ammunition to Russia.
The US said in February that the Asian country has transported more than 10,000 containers of such material since September.
A document seen by Reuters showed 40 companies are due to be added to the sanctions list.
These include Russian companies sourcing arms for the military, as well as firms in other countries that have sold electronics equipment for Russian military use.
Reuters reported these companies are based in the United Arab Emirates, Kyrgyzstan, Turkey and China.
They are accused of selling on products originating in the EU and US.
The EC declined to comment.
Unilateral LNG import bans
Earlier in April, EU member states agreed to allow individual governments to ban imports of Russian LNG.
The European Parliament voted to pass rules that would allow countries to stop Russian companies from booking gas infrastructure capacity, Reuters reported.
Under new EU gas market rules, governments will be able to put a temporary halt on Russian and Belarusian gas exporters from bidding for capacity on the infrastructure needed to deliver piped gas and LNG into Europe.
But it also specifies that restricting Russian gas imports cannot disrupt flows of gas between EU countries, which could have implications for the re-export of LNG cargoes and pipeline flows between states.
