There will be “significant consequences” for the EU-Israel relationship if Israel extends its sovereignty to parts of the West Bank, European Union High Commissioner for Foreign Affairs Josep Borrell warned in remarks to the European Parliament on Thursday.

“Annexation would inevitably have significant consequences for the close relationship we currently enjoy with Israel,” Borrell said. “I will not prejudge the specific impact of a possible annexation, but let me underline that the EU has its own obligations and responsibility under international and EU law.”

Borrell added that he is using all of the EU’s “diplomatic capacities in order to put pressure for that not to happen” and that he expressed “the gravity of such an announcement” in conversations with Alternate Prime Minister Benny Gantz and Foreign Minister Gabi Ashkenazi.

At the same time, Borrell admitted that “it is difficult to find unanimity” on the matter – referring to opposition from Hungary, Austria and the Czech Republic to past warnings he released – though there is “a strong, very strong majority of countries that continue supporting a negotiated two-state solution based on international parameters and considering that any annexation would be against international law.”

Israeli Prime Minister Benjamin Netanyahu has said that he plans to take steps to annex large swathes of the occupied West Bank and Jordan Valley from 1 July, as part of the US’ so-called “peace plan” for the region.

The West Bank, including East Jerusalem, is designated as occupied territory under international law. As a result, all Jewish settlements, as well as the planned annexation, are illegal.

Annexation is part of US President Donald Trump’s “peace plan” which was announced on 28 January. It refers to Jerusalem as “Israel’s undivided capital” and recognises Israeli sovereignty over large parts of the West Bank.