Egyptian authorities have detained more than 200 pro-Palestinian activists in Cairo ahead of an international march with the stated aim of breaking Israel's blockade on Gaza, organizers said Thursday.

As part of the Global March to Gaza, thousands of activists planned to travel to Egypt's Rafah border crossing with the Palestinian territory on Friday to demand the entry of humanitarian aid.

The U.S. embassy in Jerusalem announced Thursday it was restricting staff movements, after President Donald Trump said U.S. personnel were being moved from the potentially "dangerous" Middle East.

"Due to the increased regional tensions, U.S. government employees and their family members are restricted from travel outside the greater Tel Aviv (area)... Jerusalem, and Be'er Sheva areas until further notice," the embassy said in a statement.

An Israeli NGO representing activists detained aboard a boat attempting to breach Israel's blockade of Gaza said Thursday that six were en route to the airport for deportation.

"After more than 72 hours in Israeli custody following the unlawful interception of the Madleen Freedom Flotilla in international waters... six volunteers are now being transferred to Ben Gurion Airport for deportation," the Adalah rights group said in a statement.

Iran and the United States will hold a sixth round of negotiations over Tehran's rapidly advancing nuclear program this Sunday in Oman, the sultanate's foreign minister said Thursday, as regional tensions have spiked in recent days.

The announcement by Oman's Foreign Minister Badr al-Busaidi comes as the U.S. is drawing down the presence of staffers who are not deemed essential to operations in the Middle East and their loved ones due to the potential for regional unrest.

Beijing slammed on Thursday what it called "dangerous behavior" by a Japanese military plane over the Pacific, after Tokyo said Chinese fighter jets flew "unusually close" to its aircraft at the weekend.

"The root cause of the risk to maritime and air security was the close reconnaissance of China's normal military activities by a Japanese warplane," foreign ministry spokesman Lin Jian said.

The Palestinian Authority on Thursday said internet and fixed-line communication services were down in Gaza following an attack on the territory's last fiber optic cable, accusing Israel of being behind it.

"All internet and fixed-line communication services in the Gaza Strip have been cut off following the targeting of the last remaining main fiber optic line in Gaza," the PA's telecommunications ministry said in a statement, accusing Israel of attempting to cut off Gaza from the world.

Iran said Thursday it will build a new uranium enrichment facility after the United Nations nuclear watchdog adopted a resolution criticizing Iran for "non-compliance" with its obligations.

"The necessary orders have been issued by the head of the Atomic Energy Organization to launch a new enrichment center in a secure location," said a joint statement from the organization and the foreign ministry, adding that "other measures... will be announced later".

One person was killed on Wednesday in an Israeli strike on a village in southern Lebanon, the health ministry and Israel's military said, the latest deadly attack since a November ceasefire.

"The raid carried out by an enemy Israeli drone on the town of Beit Lif, in the Bint Jbeil district, resulted in one martyr and three people injured," read a statement from the ministry.

Medical charity Medecins du Monde Wednesday accused Israel of violating international law with drone strikes on a building housing one of its offices in war-torn Gaza that killed eight people, none of them staff.

The France-based aid group said in a statement the attack on Tuesday "constitutes a serious violation of international humanitarian law, which protects both civilian populations and humanitarian organizations operating in conflict zones".

U.S. President Donald Trump said he was less confident than a few months ago about prospects for reaching a deal with Iran over its nuclear program, speaking in a podcast aired Wednesday.

The two countries appear to be locked in a standoff over uranium enrichment nearly two months into the high-stakes negotiations.