U.S. President Joe Biden is leaving in a week on a five-day, three-nation trip to Europe, the White House said Sunday, with the key stop at the annual NATO summit in Vilnius, Lithuania, where Western leaders plan to discuss their latest efforts to bolster Ukraine’s fight against Russia.

Biden is heading first to London next Sunday on the July 9-13 trip, where over two days he is planning to meet with King Charles and Prime Minister Rishi Sunak “to further strengthen the close relationship between our nations,” the White House said.

The U.S. leader then heads to Lithuania for two days of NATO meetings where leaders of the 31-nation Western military alliance will discuss the state of Ukraine’s counteroffensive to recapture territory in the southeastern part of the country that Russia took in the earliest stages of 16 months of fighting.

NATO countries, led by the United States, have sent billions of dollars of armaments to Ukraine, but Russian aerial bombardments have continued to kill dozens of Ukrainian civilians even as Kyiv’s forces have shot down hundreds of incoming missiles. The ones that have landed have proved devastating, killing people and destroying their residential buildings.

After the NATO summit, Biden is heading to Helsinki, the Finnish capital, to commemorate Finland recently joining the military alliance created in the aftermath of World War II, and to meet with Nordic leaders.

Biden did not attend Charles’s coronation in London in May, instead sending first lady Jill Biden to represent the U.S. Biden last month hosted Sunak at the White House.

NATO Secretary-General Jens Stoltenberg also met with Biden at the White House last month, where the two leaders pledged their continued support of Ukraine in its war against Russia.

“The NATO allies have never been more united. We both worked like hell to make sure that happened. And so far, so good,” Biden said as he sat alongside Stoltenberg.

Finland joined NATO in April, effectively doubling Russia’s border with the world’s biggest security alliance. Biden has characterized the strengthened NATO alliance as a sign of Moscow’s declining influence.

Sweden is also seeking entry into NATO, although alliance members Turkey and Hungary have yet to endorse the move. Biden is hosting Sweden’s prime minister, Ulf Kristersson, at the White House on Wednesday as a show of support for its bid for NATO membership.

Turkey President Recep Tayyip Erdogan has said Sweden is too lax on terrorist groups and security threats, while Stoltenberg has said Sweden has met its obligations for NATO membership by toughening anti-terrorist laws and other measures. Hungary’s reasons for opposing Sweden have been less defined, complaining about Sweden’s criticism of democratic backsliding and the erosion of the rule of law.

All NATO nations have to ratify the entry of new member countries.

Some material in this report came from The Associated Press.