Lead­ers of the world’s most pow­er­ful democ­ra­cies gath­ered Thurs­day for Group of Sev­en meet­ings in Hi­roshi­ma, with Rus­sia’s in­va­sion of Ukraine high on the agen­da for a sum­mit con­vened in the shad­ow of the world’s first atom­ic bomb at­tack.

The G7 na­tions, which of­fi­cials said have reached new lev­els of co­op­er­a­tion more than a year in­to Rus­sia’s bru­tal war, were set to un­veil a new round of sanc­tions against Moscow when the sum­mit of­fi­cial­ly opens on Fri­day, as well as an­nounce that they would re­dou­ble their ef­forts to en­force ex­ist­ing sanc­tions meant to sti­fle Rus­sia’s war ef­fort and pun­ish those be­hind it, a U.S. of­fi­cial said.

The of­fi­cial, speak­ing on the con­di­tion of anonymi­ty to pre­view the an­nounce­ment, said the U.S. com­po­nent of the ac­tions would black­list about 70 Russ­ian and third-coun­try en­ti­ties in­volved in Rus­sia’s de­fense pro­duc­tion, and sanc­tion more than 300 in­di­vid­u­als, en­ti­ties, air­craft and ves­sels.

The of­fi­cial added that the oth­er na­tions in the group would un­der­take sim­i­lar steps to fur­ther iso­late Rus­sia and to un­der­mine its abil­i­ty to wage war in Ukraine. De­tails were to come out over the course of the week­end sum­mit.

Japan­ese Prime Min­is­ter Fu­mio Kishi­da, who is host­ing the sum­mit in his home­town, opened the glob­al diplo­ma­cy with a sit-down with U.S. Pres­i­dent Joe Biden af­ter Biden’s ar­rival at a near­by mil­i­tary base. Kishi­da al­so held talks with British Prime Min­is­ter Rishi Sunak be­fore the three-day gath­er­ing of lead­ers opens.

The Japan-U.S. al­liance is the “very foun­da­tion of peace and se­cu­ri­ty in the In­do-Pa­cif­ic re­gion,” Kishi­da told Biden in open­ing re­marks.

“We very much wel­come that the co­op­er­a­tion has evolved in leaps and bounds,” he said.

Biden, who greet­ed U.S. and Japan­ese troops at near­by Ma­rine Corps Air Sta­tion Iwaku­ni be­fore his meet­ing with Kishi­da, said: “When our coun­tries stand to­geth­er, we stand stronger, and I be­lieve the whole world is safer when we do.”

As G7 at­ten­dees made their way to Hi­roshi­ma, Moscow un­leashed yet an­oth­er aer­i­al at­tack on the Ukrain­ian cap­i­tal. Loud ex­plo­sions thun­dered through Kyiv dur­ing the ear­ly hours, mark­ing the ninth time this month that Russ­ian air raids have tar­get­ed the city af­ter weeks of rel­a­tive qui­et.

“The cri­sis in Ukraine: I’m sure that’s what the con­ver­sa­tion is go­ing to start with,” said Matthew P. Good­man, se­nior vice pres­i­dent for eco­nom­ics at the Cen­ter for Strate­gic and In­ter­na­tion­al Stud­ies.

Speak­ing to re­porters aboard Air Force One, Jake Sul­li­van, the White House na­tion­al se­cu­ri­ty ad­vis­er, said there will be “dis­cus­sions about the bat­tle­field” in Ukraine and on the “state of play on sanc­tions and the steps that the G7 will col­lec­tive­ly com­mit to on en­force­ment in par­tic­u­lar.”

Rus­sia is now the most-sanc­tioned coun­try in the world, but there are ques­tions about the ef­fec­tive­ness of the fi­nan­cial penal­ties de­spite their breadth.

The U.S., for ex­am­ple, has frozen Russ­ian Cen­tral Bank funds, re­strict­ed banks’ ac­cess to SWIFT -- the dom­i­nant sys­tem for glob­al fi­nan­cial trans­ac­tions -- and sanc­tioned thou­sands of Russ­ian firms, gov­ern­ment of­fi­cials, oli­garchs and their fam­i­lies.

The Group of Sev­en na­tions col­lec­tive­ly im­posed a $60 per-bar­rel price cap on Russ­ian oil and diesel last year, which the U.S. Trea­sury De­part­ment on Thurs­day de­fend­ed in a new progress re­port, stat­ing that the cap has been suc­cess­ful in sup­press­ing Russ­ian oil rev­enues. Trea­sury cites Russ­ian Min­istry of Fi­nance da­ta show­ing that the Krem­lin’s oil rev­enues from Jan­u­ary to March this year were more than 40% low­er than last year.

The eco­nom­ic im­pact of sanc­tions de­pends large­ly on the ex­tent to which a tar­get­ed coun­try is able to cir­cum­vent them, ac­cord­ing to a re­cent Con­gres­sion­al Re­search Ser­vice re­port. So, for the past month, U.S. Trea­sury of­fi­cials have trav­elled across Eu­rope and Cen­tral Asia to press coun­tries that still do busi­ness with the Krem­lin to cut their fi­nan­cial ties.

G7 lead­ers and in­vit­ed guests from sev­er­al oth­er coun­ties are al­so ex­pect­ed to dis­cuss how to deal with Chi­na’s grow­ing as­sertive­ness and mil­i­tary build-up as con­cerns rise that it could try to seize Tai­wan by force, spark­ing a wider con­flict. Chi­na claims the self-gov­ern­ing is­land as its own and its ships and war­planes reg­u­lar­ly pa­trol near it.

Se­cu­ri­ty was tight in Hi­roshi­ma, with thou­sands of po­lice de­ployed through­out the city. A small group of pro­test­ers was con­sid­er­ably out­num­bered by po­lice as they gath­ered Wednes­day evening be­side the ru­ins of the Atom­ic Peace Dome memo­r­i­al, hold­ing signs in­clud­ing one which read “No G7 Im­pe­ri­al­ist Sum­mit!”

In a bit of du­elling diplo­ma­cy, Chi­nese Pres­i­dent Xi Jin­ping is host­ing the lead­ers of the Cen­tral Asian coun­tries of Kaza­khstan, Kyr­gyzs­tan, Tajik­istan, Turk­menistan and Uzbek­istan for a two-day sum­mit in the Chi­nese city of Xi’an start­ing Thurs­day.

Dur­ing the meet­ing in Hi­roshi­ma, Kishi­da hopes to high­light the risks of nu­clear pro­lif­er­a­tion. The lead­ers on Fri­day are sched­uled to vis­it a memo­r­i­al park that com­mem­o­rates the 1945 atom­ic bomb­ing by the U.S. that de­stroyed the city and killed 140,000 peo­ple.

North Ko­rea’s nu­clear pro­gram and a spate of re­cent mis­sile tests have crys­tal­ized fears of a po­ten­tial at­tack. So have Rus­sia’s threats to use nu­clear weapons in Ukraine. Chi­na, mean­while, is rapid­ly ex­pand­ing its nu­clear ar­se­nal.

The lead­ers are due to dis­cuss ef­forts to strength­en the glob­al econ­o­my and ad­dress ris­ing prices that are squeez­ing fam­i­lies and gov­ern­ment bud­gets around the world, par­tic­u­lar­ly in de­vel­op­ing coun­tries in Africa, Asia and Latin Amer­i­ca.

The de­bate over rais­ing the debt lim­it in the U.S., the world’s largest econ­o­my, has threat­ened to over­shad­ow the G7 talks. Biden plans to hur­ry back to Wash­ing­ton af­ter the sum­mit for debt ne­go­ti­a­tions, scrap­ping planned meet­ings in Papua New Guinea and Aus­tralia.

The British prime min­is­ter ar­rived in Japan ear­li­er Thurs­day and paid a vis­it to the JS Izu­mo, a ship that can car­ry he­li­copters and fight­er jets able to take off and land ver­ti­cal­ly.

Dur­ing their bi­lat­er­al meet­ing Thurs­day, Sunak and Kishi­da an­nounced a se­ries of agree­ments on is­sues in­clud­ing de­fense; trade and in­vest­ment; tech­nol­o­gy, and cli­mate change, Sunak’s of­fice said.

The G7 in­cludes Japan, the Unit­ed States, the Unit­ed King­dom, France, Ger­many, Cana­da and Italy, as well as the Eu­ro­pean Union.

A host of oth­er coun­tries have been in­vit­ed to take part. The G7 hopes to strength­en its mem­bers’ ties with coun­tries out­side the world’s rich­est in­dus­tri­al­ized na­tions, while shoring up sup­port for ef­forts like iso­lat­ing Rus­sia.

Lead­ers from Aus­tralia, Brazil, In­dia, In­done­sia and South Ko­rea are among those par­tic­i­pat­ing as guests. Ukrain­ian Pres­i­dent Volodymyr Ze­len­skyy is ex­pect­ed to join by video link.  —HI­ROSHI­MA, Japan (AP)

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Sto­ry by ADAM SCHRECK and ZEKE MILLER | As­so­ci­at­ed Press

As­so­ci­at­ed Press writ­ers Josh Boak in Hi­roshi­ma and Fa­ti­ma Hus­sein in Wash­ing­ton con­tributed to this re­port.