The fate of the valley is a sticking point in US-led negotiations that seek to produce a deal on setting up a Palestinian state alongside Israel. The Palestinians want that state to include the West Bank, Gaza Strip and east Jerusalem, territories Israel captured in 1967.
The Jordan Valley would form the eastern border of a Palestinian state with Jordan.
Israel seeks a long-term military presence in the valley even after any deal, citing security concerns, including the possible influx of weapons and militants from the east. Palestinian President Mahmoud Abbas
has said he would consider a gradual Israeli troop withdrawal from a Palestinian state over five years, but not longer.
Palestinians say they need the sparsely populated valley as the breadbasket of their future state and for resettling Palestinian refugees who would return from exile. Israel has sharply restricted Palestinian development in the valley, critics say, maintaining control over most of the land in the area.
The UN Office for the Coordination of Humanitarian Affairs said Israel demolished 390 Palestinian-owned structures in the valley in 2013, up from 172 the year before. Some 590 Palestinians were displaced last year, compared to 279 in 2012, the agency said.
Israeli officials had no immediate comment on the demolitions, but Israel has said in the past it demolishes structures set up without permits.
Elsewhere in the West Bank, a Palestinian district official, Ghassan Daghlas, said about 100 olive trees were damaged in the night from Tuesday to Wednesday in an alleged attack by militant settlers near the village of Yanoun.
On the outskirts of another village, Qusra, militant settlers, some of them masked and armed, approached Palestinian farmers working their land Thursday and demanded that they leave, said village resident Ahmed Talat. A scuffle ensued, he said. The military arrived, Palestinians threw stones and soldiers fired tear gas, Talat said.
The military said soldiers dispersed the stone-throwers. It had no immediate comment on the alleged settler attack near Yanoun.
Also Thursday, the EU foreign policy chief urged Israel to reverse its decision to approve building permits for 558 apartments in Jewish settlements in east Jerusalem. Municipal planners approved the permits Wednesday.
"These plans could put at risk the prospects of Jerusalem becoming the capital of two states and, in particular, the territorial contiguity between east Jerusalem and the southern West Bank," Catherine Ashton said in a statement.