JERUSALEM (AP) — Israel’s fragile governing coalition faced a crisis on Wednesday after Bedouins staged protests against tree-planting by nationalists on disputed land in the Negev desert.

Some protesters on Tuesday evening hurled stones at vehicles on a highway near Beersheba, blocked the railway line and torched a vehicle. Police said two officers were injured in the violence and local media reported at least 18 people arrested.

The conflict over planting trees in the Negev in southern Israel - home to Bedouin villages unrecognized by the state - has divided the government.

Foreign Minister Yair Lapid called for halting the planting and reassessing the situation while the Islamist Ra’am party has threatened to withhold its votes in parliament in protest. Both are members of the fragile eight-party coalition that runs the government.

Ra’am, the Islamist party, secured four seats in the 120-member Knesset, Israel’s parliament, in last year’s elections, with strong support among Bedouin citizens of Israel. Party leader Mansour Abbas wrote on Twitter that “a tree is not more important than a person.”

More hawkish members of the diverse governing coalition have pledged to press on, undeterred.

Prime Minister Naftali Bennett heads an unwieldy coalition of eight parties that joined forces in June to form a government and end Israel’s protracted political deadlock. They range from the small Islamist and liberal parties to ultranationalists, and were united only in their opposition to longtime leader Benjamin Netanyahu.