A sceptical Israel has warned the international community against being fooled by Iran apparently inching closer to entertaining concessions on its nuclear programme in the face of stringent sanctions.

As talks got under way in Baghdad, defence minister Ehud Barak accused the Islamic republic of seeking "a little wriggle room" in moving towards allowing international nuclear inspectors access to sites and documentation. Earlier he warned against mistaking the "illusion of progress" for real advances.

The world "must not blink, concede nor cave at the last minute", he said, while reiterating Israel's position that it would not rule out any option, including a military one. President Barack Obama and the west were "willing to compromise" while, in contrast, "Israel is demanding a complete halt to Iranian uranium enrichment". All enriched uranium must be removed from the country. There must be no "window or crack' which the Iranians can [creep] through to advance their military nuclear programme".

On Monday, the prime minister Binyamin Netanyahu delivered a similarly uncompromising message to the six countries – the US, Britain, France, Russia, China and Germany – involved in Wednesday's talks in the Iraqi capital. "Iran wants to destroy Israel and it is developing nuclear weapons to fulfill that goal," Netanyahu told a conference in Jerusalem. "Against this malicious intention, leading world powers need to display determination and not weakness. They should not make any concessions to Iran."

And foreign minister Avigdor Lieberman told his UK counterpart William Hague in London that the Iranians were trying to create a more positive atmosphere during the talks while pursuing their goal of acquiring nuclear weapons.

Dan Margalit, an influential media commentator, delivered the same message in blunt language. "The free world is pulling a fast one on us. And on itself. The agreement that the International Atomic Energy Agency reached with Iran is a pact among thieves. Thieves and liars. Everyone knows that this deal is not worth even the few words used to announce it."

Efforts to stop the Iranian nuclear programme had become "sapped of energy" as the threat of an Israeli military strike had diminished in the public's mind in recent weeks, he wrote in Israel Hayom, the country's largest circulation newspaper.

"Netanyahu and Barak …can restore credibility to the Israeli military threat, and reignite a real concern among the Iranians. That is, if the world hasn't missed the boat on the military threat as well."

Israel fears that it could lose the opportunity for military action if Iran moves its enrichment facilities underground. A strike in September or October, before the "zone of immunity" is reached and ahead of the US election, is still considered possible by many analysts.