Following massive explosions at a military depot in the Russian-occupied Crimean Peninsula, Ukrainian President Volodymyr Zelenskyy told people there and in other parts of southern Ukraine to “be very careful” and avoid areas where Russian forces store ammunition and equipment.

“The reasons for the explosions in the occupied territory can be different, very different, in particular, I quote the definition of the occupiers themselves, ‘bungling,’” Zelenskyy said in his latest address. “But they all have the same meaning: the destruction of the occupiers’ logistics, their ammunition, military and other equipment, command posts saves the lives of our people.”

The large-scale blasts Tuesday occurred at an ammunition storage facility in Mayskoye, the second time in a week that explosions have occurred at Russian outposts in the territory it seized in 2014.

Russia, without pinpointing the perpetrators, called the latest explosions an “act of sabotage.” They followed last week’s attack at the Saki air base that destroyed nine Russian warplanes.

Ukraine did not claim responsibility for the Mayskoye incident, but Ukrainian presidential adviser Mykhaylo Podolyak tweeted: “Crimea occupied by Russians is about warehouses, explosions and high risk of death for invaders and thieves. Demilitarization in action.”

Russian officials said the fires at the depot caused damage to a power plant, power lines, rail tracks and some apartment buildings, but that there were no serious injuries.

The fight for control of Crimea remains contentious, with Moscow demanding that Ukraine recognize it as part of Russia and Ukraine calling for its return to the Kyiv government before any eventual end to the war can be negotiated.

The military depot where the blasts occurred is in the north of the peninsula, about 50 kilometers from the Russian-controlled region of Kherson in southern Ukraine.

The Russian military blamed last week’s blasts at the Saki air base on an accidental detonation of munitions there, but more likely it appeared to be the result of a Ukrainian attack, with U.S. news outlets quoting unnamed Ukrainian military sources as saying their forces carried it out.

Guterres visit

U.N. Secretary-General Antonio Guterres is due to visit Ukraine on Thursday for a meeting with Zelenskyy and Turkish President Recep Tayyip Erdogan.

Guterres spokesman Stephane Dujarric told reporters that the U.N. chief would then travel Friday to the southern city of Odesa to visit a port being used as part of an initiative to restart Ukrainian grain exports. The United Nations and Turkey helped broker the agreement with Russia and Ukraine amid a global food crisis, and several ships have already departed Ukraine.

Guterres is also due to travel to Istanbul on Saturday to visit the Joint Coordination Center that is monitoring the export system, including inspections of the exports demanded by Russia.

U.S. Secretary of State Antony Blinken announced late Monday $68 million to help with “procurement, transport, and storage of up to 150,000 metric tons of Ukrainian wheat to address acute food insecurity.”

“While the resumption of exports from Ukraine’s Black Sea ports is a positive step in addressing the needs of food insecure countries, these shipments must continue so that the millions of tons of food trapped in the country can reach markets and help feed the world’s most vulnerable,” Blinken said in a statement.