Israel is considering whether to conclude an agreement committing it to dialogue with the European Union on weapons of mass destruction for the first time.
Israel, which is not a signatory to the nuclear non-proliferation treaty, is widely believed to have the Middle East's only nuclear weapons arsenal but has never officially admitted it.
The European Commission is due to adopt action plans negotiated with seven countries on Thursday, including Israel, under the EU's European Neighbourhood Programme, but it will not know until the last minute whether the Jewish state accepts the text.
An Israeli diplomat said there was a high-level debate in Israel about whether the clause set an unacceptable precedent by forcing the Jewish state to hold talks on its WMD policy. "It won't be decided before Wednesday," he said.
"Israel has never put in a formal document before its willingness to discuss these issues. Some people in Israel argue that this is a serious deviation from Israeli policy."
Since the EU adopted its the Neighbourhood Programme in 2002, it has insisted on WMD clauses in agreements, including most recently Syria and Iran. "We have to show that we are even-handed by insisting on this with Israel as well as Syria or Iran," a Commission official said.
The action plan would also require Israel to hold a regular dialogue with the EU on its human rights record, but diplomats said the wording of the WMD clause was the most sensitive issue.