A senior US official told reporters on Friday that it was “quite possible” the P5+1 and Iran could reach an agreement regarding the Islamic Republic’s nuclear program when diplomats meet in Geneva this week.

“I don’t know if we will reach an agreement. I think it is quite possible that we can, but there are still tough issues to negotiate,” the official, who spoke on condition of anonymity, was quoted by Reuters as saying.

In the previous round of talks, which took place earlier this month, a potential agreement was scuttled when the US, under pressure from France, inserted last-minute changes into a working draft, Russian Foreign Minister Sergey Lavrov said on Thursday.

Speaking in Cairo, Lavrov said the United States had amended the draft in response to French demands and circulated it for approval “literally at the last moment, when we were about to leave Geneva,” without consulting Iran. His comments were reported by Voice of Russia.

Earlier Friday, Prime Minister Benjamin Netanyahu took to Twitter to keep up pressure on Western powers over negotiations with Iran on its contested nuclear program and to warn against rushing into a “bad deal.”

In his latest salvo against making concessions to Iran, Netanyahu’s Twitter account featured a cartoon-like ad that detailed what he said the pending agreement included.

“The proposal enables Iran to develop atomic bombs and build long-range missiles to reach the US and Europe,” it read. “Iran is getting everything and giving nothing.”

Netanyahu has been increasingly vocal in recent days about his opposition to a potential deal between six Western powers and Iran that would ease some sanctions while still leaving Iran with uranium-enrichment capabilities. Netanyahu has said he utterly rejects the brewing agreement and has been lobbying American allies in Congress to keep up sanctions.

US Secretary of State John Kerry met with Netanyahu three times last week in Israel to discuss the negotiations and US President Barack Obama followed up with a phone call to try and ease the Israeli leader’s concerns. Israel highlights relentless anti-Israeli rhetoric issued by Iran, and its support for Islamic extremist groups in southern Lebanon and Gaza, and has insisted that Tehran must be prevented from attaining a nuclear weapons capability. If necessary, Netanyahu told the UN General Assembly six weeks ago, Israel would “stand alone” to thwart the Iranian nuclear program.

The Associated Press contributed to this report.