WASHINGTON (Reuters) - Republican and Democratic U.S. senators said Russia refused to grant them visas for a visit to Moscow next week, amid disagreement within Washington and among U.S. allies over whether the country should be readmitted to the Group of Seven.

FILE PHOTO: Senator Chris Murphy (D-CT) speaks after the senate voted on a resolution ending U.S. military support for the war in Yemen on Capitol Hill in Washington, U.S., December 13, 2018. REUTERS/Joshua Roberts

Democratic Senator Chris Murphy said on Tuesday that Russia denied him a visa. Senator Ron Johnson, a Republican, said on Monday that his visa request had been denied, which he called “a petty affront.”

President Donald Trump said last week it would be appropriate to let Russia return to the G7 group of advanced industrialized countries, telling reporters that former Democratic President Barack Obama had wanted Russia out of what used to be the G8 but he thought it was “much more appropriate” to include the country.

Other G7 countries have objected.

Murphy and Johnson are Senate Foreign Relations Committee members and have pushed for sanctions. Another Republican, Senator Mike Lee, was issued a visa and intended to visit Russia, a spokesman for Lee said.

“With the collapse of recent arms control agreements and significant domestic opposition to Vladimir Putin’s authoritarian rule, this is potentially a perilous moment for our two nations’ fragile relationship, and it’s a shame that Russia isn’t interested in dialogue,” Murphy said in a statement.

The Russian embassy in Washington did not respond to a request for comment. But it tweeted a statement saying Johnson had not applied for a visa at the embassy. The tweet also called Johnson “russophobic” and scoffed at his saying he wanted to restore direct dialogue with Russian parliamentarians.

While it had been unusual for U.S. lawmakers to be denied travel visas, Russia has done so several times in recent years, especially those who have pushed for sanctions against Moscow over its aggression toward Ukraine and interference in U.S. elections.

And Israel this month barred two Democratic lawmakers, U.S. Representatives Rashida Tlaib and Ilhan Omar, the first two Muslim women elected to Congress, shortly after Trump called on his ally not to let them in.

Separately, senior Democratic senators said on Tuesday they had written to Trump expressing strong opposition to readmitting Russia to the G7, citing its invasion of Crimea.

The letter was signed by Senators Chuck Schumer, the Democratic leader in the Senate, as well as Jack Reed, Bob Menendez and Mark Warner, the top Democrats on the Armed Services, Foreign Relations and Intelligence committees, respectively.