Ukraine accuses Russia of launching invasion

Two columns of Russian tanks and military vehicles fired Grad missiles at a border post in southeastern Ukraine, then rolled into the country Thursday as Ukraine's overmatched border guards fled, a top Ukrainian official said.

The comments, by Col. Andriy Lysenko, a spokesman for Ukraine's National Security Council, and statements from NATO, pro-Russian separatists in Ukraine and the United States left little doubt that the Russian military entered southeastern Ukraine.

A top NATO official said at least 1,000 Russian troops have poured into Ukraine with sophisticated equipment and have engaged Ukrainian soldiers, resulting in casualties. He called that a conservative estimate and said an additional 20,000 Russian troops were right over the border.

"Russian forces have entered Ukraine," Ukrainian President Petro Poroshenko said Thursday, canceling a trip to Turkey for the inauguration of newly elected president Recep Tayyip Erdogan and calling an emergency meeting of his security council.

"Today the president's place is in Kiev," Poroshenko said, as the strategic southeastern Ukraine town of Novoazovsk appeared firmly under the control of Russian-backed separatists.

Novoazovsk, which lies along the road connecting Russia to the Russian-annexed Crimean Peninsula, came under shelling for three days, with the rebels entering on Wednesday. The loss of Novoazovsk is a blow to Kiev's forces, since it leaves vulnerable Mariupol, a port city of 450,000 people about 20 miles west along the coast.

Pro-Russian rebel forces said they are seeking to create a land link between Russia and Crimea. If successful, it could give them or Russia control over the entire Sea of Azov and the gas and mineral riches that energy experts believe lie beneath it. Ukraine lost roughly half its coastline, several major ports and significant Black Sea mineral rights in March when Russia annexed Crimea.

A military source said the separatist forces had also taken Savur-Mohyla, a hill east of Donetsk that gives strategic command over large areas of the territory.

The actions coincided with Ukrainian Prime Minister Arseny Yatsenyuk's appeal to the international community on Thursday to penalize Russia unless its forces withdrew from Ukrainian territory. At a government meeting, Yatsenyuk asked the United States, the European Union and the G-7 "to freeze Russian assets and finances until Russia withdraws armed forces, equipment and agents."

Meanwhile, Poroshenko, who canceled a visit to Turkey for the inauguration of newly elected president Recep Tayyip Erdogan, called a snap session of Ukraine's security council.

In Mariupol a brigade of Ukrainian forces arrived at the airport on Wednesday afternoon, and deep trenches were dug a day earlier on the city's edge.

In other developments, 11 people were killed in Donetsk, the largest rebel-held city, by shelling during the night, the city administration said in a statement.

The U.S. government has accused Russia of orchestrating a new military campaign in Ukraine that is helping rebel forces expand their fight and sending in tanks, rocket launchers and armored vehicles.

"These incursions indicate a Russian-directed counteroffensive is likely underway in Donetsk and Luhansk," State Department spokeswoman Jen Psaki said Wednesday. Russian forces, she said, are being sent 30 miles inside Ukraine, without them or their families knowing where they are going. She cited reports of burials in Russia for troops who died in Ukraine and wounded Russian soldiers being treated in a St. Petersburg hospital.

The new fighting follows Russian President Vladimir Putin's and Poroshenko's meeting in the Belarusian capital, Minsk, on Tuesday for their first one-on-one meeting as presidents. There was no indication of a swift resolution to the fighting that has dragged on since April and claimed at least 2,000 civilian lives — not including the 298 who perished when a Malaysian Airlines flight was shot down over rebel-held territory last month.

Poroshenko called the talks "overall positive" and said Putin accepted the principles of his peace plan, which includes amnesty for those in the east not accused of serious crimes and calls for some decentralization of power.

Putin, however, insisted that only Kiev could secure a cease-fire deal with the pro-Moscow separatists, saying the conflict was "Ukraine's business" because Russia was not in the fight. Russia "can only help to create an atmosphere of trust for this important and necessary process," he said. "We in Russia cannot talk about any conditions for the cease-fire.”

Al Jazeera and wire services