United States President Donald Trump on Monday signed a proclamation recognising Israel’s sovereignty over the disputed Golan Heights, an area seized from Syria in 1967, AFP reported.

Syria said the US president’s decision was “a blatant attack on its sovereignty” and it was determined to recover the area “through all available means”, BBC reported. Israel annexed the Golan Heights in 1981, but the move has not been recognised internationally.

“Today, aggressive acts by Iran and terrorist groups, including Hizballah, in southern Syria continue to make the Golan Heights a potential launching ground for attacks on Israel,” Trump said while signing the proclamation. “Any possible future peace agreement in the region must account for Israel’s need to protect itself from Syria and other regional threats.”

The move comes as an election boost for Israel Prime Minister Benjamin Netanyahu amid allegations of corruption and accusations that he used his position for personal gain.

Netanyahu called the recognition historic and said the Golan Heights would remain permanently under Israeli control. “We shall never give it up,” he said. “Your proclamation comes at a time when Golan is more important than ever for our security.”

For decades, the US took the same line as the United Nations, which said Israeli annexation of Golan Heights was “null and void”. Last week, Trump tweeted that it was time for the US to recognise Israel’s sovereignty over the area.

Stephane Dujarric, a spokesperson for United Nations Secretary-General Antonio Guterres, said on Monday that the UN chief’s position on the status of Golan remains unchanged, AP reported.

Russia condemned Trump’s recognition, warning of a “new wave” of tensions in the Middle East in the wake of shift in US policy, reported AFP. Foreign Ministry spokesperson Maria Zakharova said the move “ignored all international procedures”.

Turkish Foreign Minister Mevlut Cavusoglu said the US has “ignored international law” by recognising Israel’s sovereignty over the Golan Heights. “However, this decision will never legitimize Israeli occupation,” he tweeted. “On the contrary, it will further increase tensions in the region by preventing peace efforts in the Middle East.”

Lebanon said Golan Heights are “Syrian Arab” territory and “no country can falsify history by transferring” land from one country to another.