(Reuters) - Senate Majority Leader Mitch McConnell said on Tuesday the U.S. Senate would vote on a bill to toughen sanctions on Iran if international negotiators miss a deadline at the end of this month for reaching a framework nuclear agreement.

"Another heavy dose of sanctions would be an appropriate remedy if there's no agreement at all," McConnell told a weekly news briefing.

If there is an agreement, he said lawmakers would move ahead on a bill that would require President Barack Obama to submit the deal for Congress' approval.

Obama has threatened to veto both bills.

Democrats in the Senate pushed to delay both measures until at least mid-April to give negotiations more breathing room. The United States and five other world powers suspended talks with Iran in Switzerland on Friday and will reconvene this week to try to break a deadlock over Tehran's atomic research programme.

Separately, Republican Senator Mark Kirk, a co-author of the sanctions bill, told reporters on Tuesday he would introduce legislation recommending new sanctions on Iran as an amendment to a budget resolution now being considered by the Senate.

There was no immediate word on when or if that amendment might come up for a vote.

The White House says any effort to ratchet up sanctions could endanger the delicate negotiations on an agreement in which Iran would curb its nuclear programme in exchange for relief from crippling economic sanctions.

But many members of Congress, particularly Republicans, worry that Obama is so eager for an agreement with Iran that the administration will give up too much in the talks.

The White House has said the other bill impinges on Obama's authority by forcing him to obtain congressional approval for an agreement that it insists is not a treaty. Administration officials also contend that the legislation would prevent a deal from succeeding because it contains a provision that would temporarily remove Obama's ability to waive sanctions.

By Reuters