Israel’s top general said on Tuesday that its military was refreshing its operational plans against Iran and that any U.S. return to a 2015 nuclear accord with Tehran would be “wrong”, Reuters reported.

The remarks are an apparent signal to U.S. President Joe Biden to tread cautiously in any diplomatic engagement with Iran.

“A return to the 2015 nuclear agreement, or even if it is a similar accord with several improvements, is bad and wrong from an operational and strategic point of view,” Lieutenant-General Aviv Kohavi said in an address to Tel Aviv University’s Institute for National Security Studies.

Since Washington pulled out of the deal, Iran has gradually breached its key limits, building up its stockpile of low enriched uranium, enriching uranium to higher levels of purity, and installing centrifuges in ways barred by the accord.

Kohavi said those actions by Iran, which denies it is seeking atomic arms, showed it could ultimately decide to push forward rapidly towards building a nuclear weapon.