41 US senators back Iran nuclear deal

Three more US senators said they would support the Iran nuclear deal, giving President Brack Obama the votes he needs to prevent the house from passing a measure disapproving of the deal. This takes to 41 the number of lawmakers who favour the deal.

"Despite my serious concerns with this agreement, I have unfortunately become convinced that we are faced with no viable alternative," Xinhua quoted Senator Gary Peters, one of the trio, as saying.

"While this is not the agreement I would have accepted at the negotiating table, it is better than no deal at all," Senator Richard Blumenthal said.

"This agreement with the duplicitous and untrustworthy Iranian regime falls short of what I had envisioned, however, I have decided the alternatives are even more dangerous," Senator Ron Wyden said.

The decisions were made on the first day when lawmakers reassembled after a month-long recess. Six Democrats remained undecided with 38 having openly favoured the deal before the three senators' announcements on Tuesday.

The 41 senators will be more than enough to block a Republican-backed resolution to disapprove the deal and will save President Barack Obama's veto from use.

It requires approval of two-thirds lawmakers in both the House and the Senate to override the veto. The Senate has 100 members.

US lawmakers have until September 17 to vote on the Iran nuclear deal, which has been widely opposed by Republicans who control both chambers of Congress.

Republicans believe that the deal made too many concessions to Iran and still it can not stop Iran from building nuclear weapons. They threaten to kill the deal in Congress with a resolution of disapproval.

The Iran nuclear agreement was reached on July 14 after extensive negotiations between Iran and "5+1" group, namely Britain, China, France, Russia, the US and Germany.

"This deal blocks every way, every pathway that Iran might take in order to develop a nuclear weapon," President Obama said.