Updated at 1:00 p.m. ET

Ukraine's president, on a visit to embattled Mariupol in the country's east, proclaimed "this city was, is and will be Ukrainian."

Petro Poroshenko, in a fiery speech in the city, which has been surrounded for days by pro-Russia separatists, also said that 1,200 Ukrainian POWs had been handed over under the terms of a cease-fire that went into effect on Friday.

The truce has largely held despite reports of renewed shelling over the weekend.

The Associated Press reports:

"The president spoke from a stage decorated with Ukraine's blue-and-yellow colors after leading the room in singing the national anthem." 'Mariupol proved that we won't let anybody burn our city to the ground. The workers of Mariupol protected peace and calm in the city,' he said, emphasizing that in eastern Ukraine 'our most important resource is people.' "

Poroshenko's largely symbolic visit does little to resolve the growing standoff between Kiev and Moscow over the fate of the region that separates Russia from Moscow's newly annexed Crimea. The Ukrainian president insisted that he had not agreed to the cease-fire out of weakness. He reiterated that independence for the region was out of the question.

Poroshenko also said in a statement that Kiev had agreed with a number of NATO member countries to open up the direct supply of arms to Ukraine.

"An agreement was managed with a series of NATO countries on direct deliveries of modern weapons which will help us protect ourselves and win," RIA cited the statement as saying, according to Reuters.

A spokesman for Ukraine's National Security Council, Col. Andriy Lysenko, said Monday that there have been about a half-dozen rebel violations of the cease-fire, but no one had been killed and no heavy artillery has been used.

NPR's Eleanor Beardsley, reporting from Kiev, says that sentiment is echoed by the Organization for Security and Cooperation in Europe, which has about 250 monitors deployed in Ukraine.

OSCE said there had been some violations as shooting continued in the eastern Ukrainian separatist stronghold of Donetsk.

The United Nations says the estimated number of people killed in the five-month conflict has risen above 3,000, if the victims of Malaysia Airlines Flight MH17 shot down over eastern Ukraine earlier this year are included.

Meanwhile, Reuters reports that the European Union is considering a new round of sanctions targeting Russia that will prevent the country's top oil producers from raising capital on European markets.

Oil producers and pipeline operators Rosneft, Transneft and Gazprom Neft would be among the targeted entities, Reuters quotes an EU diplomat as saying.

Reuters says:

"EU sanctions, however, do not encompass the gas sector and in particular state-owned Gazprom, the world's biggest gas producer which is also the biggest gas supplier to Europe."In general, the EU sanctions on raising money in the European Union for Russian companies will apply to firms that have turnover of more than 1 trillion roubles ($26.95 billion) and half of that is generated from the sale or transport of oil, the diplomat said."The sanctions will be agreed unless by 1300 GMT [9 a.m. ET] one of the EU governments objects to the deal, that was reached by ambassadors of the 28 EU countries already on Friday night."

Update at 1:45 p.m. ET. Putin, Poroshenko Discuss 'Peaceful Resolution':

Copyright 2016 NPR. To see more, visit http://www.npr.org/.