Denmark's foreign minister on Monday slammed as "inappropriate" a planned visit by a US delegation to Greenland -- a Danish autonomous territory coveted by U.S. President Donald Trump.

President Donald Trump said Monday he would levy a 25 percent tariff across the board on any country buying oil or gas from Venezuela, as he escalates trade wars with a number of US foes and allies.

"Venezuela has been very hostile to the United States and the Freedoms which we espouse," he wrote on his Truth Social network. "Therefore, any Country that purchases Oil and/or Gas from Venezuela will be forced to pay a Tariff of 25% to the United States on any Trade they do with our Country."

A Russian missile attack on a hospital and residential area in Ukraine's northeastern city of Sumy on Monday wounded 28 people, local officials said, as Moscow and Washington held talks in Saudi Arabia on a potential ceasefire.

"Today, the enemy attacked the residential neighbourhood and infrastructure facilities in the city, including children's institutions and a hospital," acting mayor of Sumy Artem Kobzar said, adding "24 adults and four children" were wounded.

Lebanese leaders held intensives contacts with Washington and Paris to prevent Israel from bombing Beirut, a Lebanese official said Monday, after heavy Israeli strikes on the country at the weekend.

While no party has claimed responsibility for the rockets that were fired at Israel on Saturday, the Lebanese Army has arrested two Syrians in the South and questioned them as witnesses, security sources said.

Lebanese Defense Minister Michel Menassa will visit Syria on Wednesday to discuss recent tensions along the border between the two countries, a Lebanese official said.

"The defense minister will head a security delegation to Damascus to meet with his counterpart, Marhaf Abu Qasra," the official told AFP on Monday on condition of anonymity.

Iran said on Monday it was open to indirect talks with the United States, after President Donald Trump had issued an ultimatum for a new nuclear deal.

"The way is open for indirect negotiations," Foreign Minister Abbas Araghchi said, dismissing the prospect of direct talks with Washington "until there is a change in the other side's approach towards the Islamic republic".

EU foreign policy chief Kaja Kallas warned on Monday during a visit to Jerusalem that Israeli strikes on Syria and Lebanon threatened to worsen the situation.

"Military actions must be proportionate, and Israeli strikes into Syria and Lebanon risk further escalation," Kallas said at a joint news conference with Israeli Foreign Minister Gideon Saar.

Istanbul's embattled Ekrem Imamoglu was officially nominated as a presidential candidate by the opposition CHP party for the 2028 elections, a party spokesman told AFP on Monday.

The Republican People's Party (CHP) -- the main opposition party and the second largest party in parliament -- held a primary election on Sunday, at which the only candidate was Imamoglu, the main political rival of President Recep Tayyip Erdogan. Imamoglu has been arrested, interrogated, jailed and stripped of his mayorship in less than a week following a graft and terror probe that the opposition has slammed as a political "coup."

The Palestinian Prisoners Club non-governmental organization said Monday that a Palestinian 17-year-old died in Israel's Megiddo prison in unknown circumstances.

In a statement, the NGO announced "the death of Walid Khaled Abdullah Ahmad (17 years old), a minor detainee from the town of Silwad, east of Ramallah, in Megiddo Prison" in Israel, adding he was the 63rd Palestinian to die in Israeli jails since the start of the war in Gaza.