US President Barack Obama conferred with key national security advisers about nuclear talks with Iran.
"The president convened a secure video teleconference with members of his national security team," said National Security Council spokeswoman Bernadette Meehan, who participated in the discussions on Tuesday night US time.
Obama was briefed on ongoing talks in Switzerland by Secretary of State John Kerry and Secretary of Energy Ernest Moniz.
US extended deadline to reach a nuclear deal with Iran to Wednesday.