KYIV, Ukraine >> Emergency workers recovered three bodies from a school hit by a Russian strike in eastern Ukraine, officials said Friday, one of a string of attacks on the nation.

The casualties in the city of Kramatorsk followed a barrage Thursday on a densely populated area of Ukraine’s second-largest city, Kharkiv, that killed at least three people and wounded 23.

In the most significant agreement involving the warring parties so far, Russian and Ukrainian officials signed deals with the UN and Turkey to avert a global food crisis by clearing the way for the shipment of millions of tons of Ukrainian grain and some Russian exports of grain and fertilizer. Ukrainian President Volodymyr Zelenskyy said in his nightly video address the deals offer “a chance to prevent a global catastrophe — a famine that could lead to political chaos in many countries of the world, in particular in the countries that help us.”

Yet the war that has blocked those grain shipments for almost five months did not abate. Russia this week reiterated its plans to seize territories beyond eastern Ukraine, where the Russian military has been trying to conquer the Donbas region, comprising the Donetsk and Luhansk provinces.

The Ukrainian president’s office said that in one Donbas city, Kramatorsk, Russian shelling destroyed a school and damaged 85 residential buildings. Ukraine’s state emergencies agency said rescuers found three bodies in the ruins of the school, which was hit Thursday.

“Russian strikes on schools and hospitals are very painful and reflect its true goal of reducing peaceful cities to ruins,” Donetsk Gov. Pavlo Kyrylenko said in televised remarks, repeating his call for residents to evacuate.

Russia gave a different account of the attack. Defense Ministry spokesman Lt. Gen. Igor Konashenkov said Thursday’s strike killed more than 300 Ukrainian troops using Kramatorsk’s School No. 23 as their base. He said another strike destroyed a munitions depot in the southern city of Mykolaiv.

Konashenkov also said Russian forces destroyed four U.S.-supplied high mobility artillery rocket systems between July 5 and 20. The U.S. said it has supplied 12 of the multiple-rocket launchers to Ukraine. The claims could not be independently verified.

A senior U.S. defense official, who briefed reporters on condition of anonymity in line with department rules, said Thursday that Russia had not yet taken out a single HIMARS but was likely to “get lucky” and do so at some point.

The U.S. announced Friday that as part of a new $270 million security assistance package, it will deliver four more HIMARS to Ukraine. The package will allow Kyiv to acquire up to 580 Phoenix Ghost drones, about 36,000 rounds of artillery ammunition and more guided rockets known as GMLRS.

Ukrainian forces have used U.S.-made rocket launchers and tactical drones to hold at bay Russia’s larger and more heavily equipped forces. The Ukrainian military has used HIMARS, which have a longer range and better precision than similar Soviet-era systems in the Russian and Ukrainian inventory, to strike Russian munitions depots and other key targets.

In the Dnipro region of central Ukraine, three schools were destroyed in the latest Russian strikes, Ukrainian authorities said. Seven Russian missiles hit the small town of Apostolove, wounding 18 residents.

The regional governor, Valentyn Reznichenko, decried the “senseless” attack.

“There are no military goals behind it,” Reznichenko said.

In other developments Friday:

• The White House announced Friday that the U.S. is sending an additional $270 million in security assistance to Ukraine, a package that will include additional medium range rocket systems and tactical drones.

The latest tranche brings the total U.S. security assistance committed to Ukraine by the Biden administration to $8.2 billion, and is being paid for through $40 billion in economic and security aid f or Ukraine approved. by Congress in May.

The new package includes four High Mobility Artillery Rocket Systems, or HIMARS and will allow Kyiv to acquire up to 580 Phoenix Ghost drones, both crucial weapon systems that have allowed the Ukrainians to stay in the fight despite Russian artillery supremacy, according to John Kirby, the White House National Security Council’s coordinator for strategic communications. The latest assistance also includes some 36,000 rounds of artillery ammunition and additional ammunition for the HIMARS.

• The British Defense Ministry said it believes that Russia is experiencing “critical shortages” of dedicated ground-attack missiles and therefore has increased its use of air-defense missiles “in secondary ground attack mode.” The ministry said Russia has “almost certainly” deployed S-300 and S-400 strategic air defense systems designed to shoot down aircraft and missiles at long range, and that there is a “high chance” of them missing their intended targets and causing civilian casualties.

• The senior U.S. defense official said the fight for Donetsk is “likely to last through the summer,” with Russia achieving slow gains at high cost. The official said Russia is launching tens of thousands artillery rounds per day but has used a lot of “smarter munitions” and “can’t keep it up forever.”