Easing pressure on Iran over its nuclear programme at this stage would be a "historic mistake," Israeli Prime Minister Benjamin Netanyahu said on Monday.
"It would be a historic mistake to ease the pressure on Iran a moment before the sanctions achieve their objective," he said at the opening of the Israeli parliament's winter session.
In remarks a day before world powers hold a fresh round of talks with Iran over its nuclear programme, which Israel and much of the West believes is a front for building a weapons capacity, Netanyahu issued a stark warning over any move to ease sanctions.
"Particularly at this moment we must not give up on them, we must keep up the pressure," he said,.
Any move to let up on Iran would only strengthen its "uncompromising elements" and its supreme leader, Ayatollah Ali Khamenei, "will be perceived as the winner," Netanyahu said.
The two-day meeting which begins in Geneva on Tuesday will be the first such nuclear talks since Iran's President Hassan Rouhani, a reputed moderate, took office in August.
Rouhani has pledged to engage constructively to resolve the decade-long dispute over Iran's nuclear drive and ultimately secure the lifting of crippling Western sanctions.
The West has responded positively to Rouhani's overtures sparking Israeli fears of an easing of world pressure on the Islamic republic's nuclear programme.
Israel has refused to rule out a military strike to prevent Iran from going nuclear, with Netanyahu telling the UN General Assembly earlier this month that the Jewish state would act unilaterally if necessary.