As part of the effort, the European Commission, the bloc's executive arm, is in talks with the United Kingdom, according to one of the people, who asked not to be identified because the plans are private.
Later on Wednesday, EU national government representatives are expected to approve a sixth sanctions package aimed at Russia for its invasion of Ukraine. The measures will include a ban on financing, brokering services, and technical or financial assistance six months after the package is passed.
A coordinated campaign to target insurers of Russian oil shipments could severely limit Moscow's ability to fund President Vladimir Putin's war. This is because 95 percent of the world's tanker liability coverage is arranged through the International Group of P&I Clubs, a London-based insurance organization bound by European law.
Without such coverage, Russia and its customers would be forced to find alternatives for risks such as oil spills and maritime mishaps, which can quickly escalate into multibillion-dollar claims.
The EU and the UK had previously agreed to coordinate the ban, according to the Financial Times.
The insurance measures are in addition to the EU's proposal to ban seaborne imports of Russian crude within six months of the package's adoption, and refined products within eight months. While deliveries through the massive Druzhba pipeline will be temporarily spared, Germany and Poland, the largest buyers from that source, have pledged to wean themselves off Russian supplies regardless of EU action.
If both countries keep their commitments, the combined effect, along with the seaborne embargo, would be to cut 90 percent of Russian crude oil sales to the EU by the end of the year.
The EU considered even tougher measures to prohibit tankers from transporting oil to third countries, but abandoned the plans after Greece expressed concerns that such a move would necessitate international coordination.