U.S. President Donald Trump said Monday he will cut the 50-day deadline he has set Russian President Vladimir Putin to end the war in Ukraine.

"I'm disappointed in President Putin, very disappointed in him. So we're going to have to look and I'm going to reduce that 50 days that I gave him to a lesser number," Trump told reporters as he met UK Prime Minister Keir Starmer at his luxury golf course in Turnberry in western Scotland.

Thailand and Cambodia have agreed to an "immediate and unconditional" ceasefire in a significant breakthrough to resolve deadly border clashes that entered a fifth day, Malaysian Prime Minister Anwar Ibrahim said Monday.

Anwar, who chaired the talks as head of the Association of Southeast Asian Nations regional bloc, said both sides have reached a common understanding to take steps to return to normalcy following what he called frank discussions.

Gunmen killed five civilians during a "terrorist attack" on a judiciary building in southeast Iran on Saturday before being killed themselves, state media reported.

Ukrainian forces are holding back Russia's concerted summer push to break through defenses along parts of the front line, Ukraine's President Volodymyr Zelensky says.

"They are not advancing. It's very tough for our guys out there. And it's tough everywhere," Zelensky told reporters on Thursday, in comments embargoed till Friday. "It's also very hard for the Russians — and that's good for us."

The Kremlin said Friday that it was "obviously" unlikely Ukrainian President Volodymyr Zelensky and Vladimir Putin would meet within 30 days, after Kyiv suggested a leaders summit before the end of August.

"A high-level meeting can and must put a definitive end to the settlement ... Is it possible to go through such a complex process in 30 days? Well, that is obviously unlikely," Kremlin spokesman Dmitry Peskov told reporters including AFP.

Iran on Thursday reaffirmed its right to enrich uranium, saying it was "unshakable", on the eve of key talks with European powers threatening to reimpose sanctions.

"Especially after the recent war, it is important for them to understand that the Islamic Republic of Iran's position remains unshakable, and that our uranium enrichment will continue. We will not give up this right of the Iranian people," Foreign Minister Abbas Araghchi was quoted as saying by Tasnim news agency.

Tens of thousands of people sought refuge on Friday as border fighting between Thailand and Cambodia entered a second day, heightening fears of a broader conflict.

The U.N. Security Council is scheduled to hold an emergency meeting on the crisis later Friday in New York, while Malaysia, which chairs a regional bloc that includes both countries, called for an end to hostilities and offered to mediate.

Iranian and European diplomats met Friday in Istanbul to embark on the latest drive to unpick the deadlock over Tehran's nuclear program.

Representatives from Britain, France and Germany, known as the E3 nations, gathered at the Iranian consulate building for the first talks since Iran's 12-day war with Israel in June, which involved U.S. bombers striking nuclear-related facilities.

Aircraft from Lebanon, Jordan, Spain and Israel were on their way Thursday to help battle a huge wildfire in Cyprus that has claimed the lives of two people. Police were investigating reports that arsonists were to blame.

The flames have scorched more than 120 square kilometers (46 square miles) of forested hillsides in one of the worst such blazes in recent memory.

The United States on Wednesday announced the approval of $322 million in arms sales to bolster Ukraine's air defenses and its armored combat vehicles.