LONDON (AP) — British Prime Minister Boris Johnson is set to visit Saudi Arabia and meet with its crown prince for talks on oil supplies, as he stressed that the West must end its dependence on Russian energy.

Johnson will also use the trip to press Saudi Arabia to condemn Russia's invasion of Ukraine, a Foreign Office official said Tuesday.

Ahead of the trip, Johnson said Western leaders made a “terrible mistake” by letting Russian President Vladimir Putin “get away with” annexing Crimea in 2014. He wrote in the Daily Telegraph that Western “addiction” to Russian fuel had emboldened Putin's invasion of Ukraine.

“We cannot go on like this. The world cannot be subject to this continuous blackmail,” Johnson wrote. “As long as the West is economically dependent on Putin, he will do all he can to exploit that dependence."

Officials have not confirmed details about the visit to Saudi Arabia but Johnson will reportedly meet with Crown Prince Mohammed bin Salman this week in the hope the Gulf state can increase its production of fuel supplies.

The visit has met with an outcry of protest from U.K. lawmakers, coming just days after Saudi Arabia said it executed 81 people in the largest known mass execution carried out in the kingdom in its modern history.

Defending his trip, Johnson told reporters in London that “if we are going to stand up to Putin's bullying,” it will be necessary to talk to other producers.

His spokesman told reporters that Johnson will raise the issue of executions reported in Saudi Arabia during his visit.

“We routinely raise human rights issues with other countries, including with Saudi Arabia, and we’ll raise Saturday’s executions with the government in Riyadh," the spokesman said.

Johnson's government announced last week that the U.K. will phase out the import of Russian oil and oil products by the end of the year. But the U.K. is much less reliant on Russia fuel than its European allies, taking about 3% of gas from Russia, Johnson said.