The chairman of the Senate Foreign Relations Committee expressed confidence Friday that the upper chamber will ratify a key nuclear arms treaty with Russia before the year is up.

Sen. John Kerry (D-Mass.) acknowledged Republicans concerns over the Strategic Arms Reduction Treaty (START) that the Obama administration hoped would pass quickly after it was signed three months ago. But Kerry assured that it would pass before the new year.

In an interview with Bloomberg News to air this weekend, the Massachusetts senator was asked if the Senate could ratify the treaty before the November midterm elections.

"I don’t want to get into the odds-making on it," he replied. "What is important is the Senate will pass it."

Pressed on whether the Senate would vote this year, Kerry replied, "I believe we will pass it this year."

START has been put on the backburner in the midst of a hectic Senate schedule as the August recess approaches and with election-year politics at play. But President Obama has made it clear that passing the treaty is a priority, especially in light of his effort to "reset" the U.S.'s diplomatic relationship with Russia.

The vote, however, appears to be a heavy lift. It takes 67 senators to ratify a treaty, meaning that all Democrats plus eight Republicans would need to support it. But aside from Foreign Relations Committee ranking member Richard Lugar (R-Ind.), no other GOP senators back the treaty.

Republicans have expressed concern that the pact to reduce warheads and missiles could weaken U.S. missile defense. The arrest of 10 Russian spies earlier this month also dampened the will to ratify the treaty.

Kerry said he would continue to speak with Republicans about their qualms.

"And we are going to press very hard to meet the concerns of many of our colleagues on the Republican side who want to have certain questions answered, which we have requested and they are coming in now — those answers," he said. "They want a certain kind of access ... on the negotiating record. And they want assurances with respect to the modernization program on nuclear weapons.

"They ought to have that and we are willing — you know, I am going to try and get two out of three of those and the third is really up to the administration," he added. "The question on the negotiating record is the administration’s decision."