Two Ukrainian warplanes were shot down Wednesday by pro-Russian rebels, according to the Ukrainian Ministry of Defense. The footage is described as showing pro-Russian rebels examining the wreckage near the Ukraine-Russia border. (Инфо корпус)

Two Ukrainian warplanes were shot down Wednesday by pro-Russian rebels, according to the Ukrainian Ministry of Defense. The footage is described as showing pro-Russian rebels examining the wreckage near the Ukraine-Russia border. (Инфо корпус)

Separatists fighting the Kiev government claimed responsibility for shooting down two warplanes Wednesday over eastern Ukraine near where a passenger airliner crashed last week after being struck by a missile.

The attack on the warplanes came just six days after the Malaysia Airlines disaster, which has drawn international outrage and showcased the advanced firepower that apparently is available on the ground in the region. The Ukrainian military said Wednesday that the two planes were flying at nearly 17,000 feet — an altitude that is out of the reach of the shoulder-fired missiles that the rebels said they had used to down the jets. Neither the government’s nor the rebels’ claims could be verified.

Ukraine has accused Russia of supplying fresh firepower to rebels over the porous border in recent days, even as international attention has focused on a possible Russian role in the attack on Malaysia Airlines Flight 17. Although the details of Wednesday’s incident remained unclear, it was a sign that the rebels may be able to inflict significant damage on the Ukrainian military, whose major advantage over its rivals is in the air.

The pilots of the two SU-25 jets, which were among four planes that were fired upon as they were returning from a mission near the Russian border, are thought to have bailed out over rebel-held territory. Their conditions and whereabouts are unknown, and the rebels said they had initiated a search mission.

“We shot them down with MANPADS,” said rebel spokesman Sergey Kavtaradze, referring to shoulder-mounted missiles that can reach a limited altitude.

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Andriy Lysenko, a spokesman for Ukraine’s National Security and Defense Council, told reporters in Kiev that the planes were flying too high to be hit by such a weapon.

“It can be reached only by heavy missile complexes,” he said.

Lysenko alleged that the missiles that hit the two planes were fired from Russian territory.

“They were shot down very professionally. The terrorists do not have such professionals,” he said in reference to the pro-Russian rebels.

Photos that have emerged since the Flight 17 crash last Thursday suggest that Buk missile launchers that apparently were in the rebels’ possession — and one of which Ukraine said was used to down the jetliner — have been transported to Russia. But U.S. officials have said that tanks, rocket launchers and other arms continue to flow into Ukraine from Russia.

The warplanes were shot down as the first 40 bodies of Flight 17 victims were en route to the Netherlands, where they are set to be identified through DNA testing.

The Wednesday crashes in the vicinity of the Flight 17 site — about 25 miles south of its perimeter — provided an eerie reminder that the international shock over a missile strike on a passenger airliner has done little to deter the rebels from continuing to shoot down aircraft. It may even have given them some latitude, because commercial airliners now avoid flight paths over eastern Ukraine.

The Ukrainian military, which says it is observing a cease-fire within a 25-mile radius of the Flight 17 crash site, is engaged in an operation to squeeze separatists out of the towns and villages encircling their stronghold of Donetsk.

Military officials say rebel forces are abandoning positions on the outskirts of Donetsk and regrouping in the city’s center.

A top rebel leader dismissed the retreat’s significance. “It’s a tactical retreat,” Pavel Gubarev told Russian state-run Rossiya 24 television. “It was all planned. Nobody has orders to fight to the bitter end. Tactical retreats are permissible. It’s normal military tactics.”

The government claims to have regained control of several cities in the Donetsk and Luhansk regions, where the separatists rose up in April and established “people’s republics,” appointing new mayors and officials.

Ukraine’s antiterrorism operation, as the government calls its military campaign against the separatists, said Wednesday that it had “liberated” the towns of Karlivka, Netaylovo and Pervomayske near Donetsk. It said the Ukrainian flag is flying again in the towns, “as a symbol of peace returning to these places.”

Aleksey Dmitrashkovsky, a spokesman for the Ukrainian military, said that in the city of Kramatorsk, also in the Donetsk region, separatists are shedding their uniforms and dressing as taxi drivers and market vendors. But he said the government will find and punish those who fought against the Ukrainian state and military.

“We’re going to find everyone,” he said. “Everyone who ever raised a hand to a Ukrainian soldier. Everyone who ever committed a crime against the state of Ukraine. Each and every one who caused women to shed tears and who stole the smiles from children. They will be held responsible under Ukrainian law.”

The sounds of pitched battles could be heard through a wide swath of rebel-held eastern Ukraine on Wednesday, including near the crash site.

In the town of Torez, a large explosion rattled shop windows and halted conversations. All afternoon — both before and after the planes were shot down — jets could be heard over the region, but they could not be seen on the partly cloudy day. They circled at a high altitude, even as an observation mission from the Organization for Security and Cooperation in Europe was directly beneath in the village of Petropavlivka.

There, OSCE officials were examining for the first time a fragment of the Malaysia Airlines plane’s fuselage that is marked with small dents, as though from shrapnel — a potentially key piece of information for investigators that has been sitting unguarded for days, propped against a light pole on the street.

Even the rebels apparently now agree with U.S. and Ukrainian assertions that a Buk antiaircraft missile system downed Flight 17, although the separatists continue to blame the Ukrainian military.

“In an attack from the air, say by a fighter or other aircraft, the missile reacts to heat and, as a rule, hits the engine. Here the picture is somewhat different,” a rebel leader, Andrei Purgin, told the Russian news agency Interfax on Wednesday.

“The distinctive feature of Buk-type systems is that they attack the forebody of the aircraft,” he said. “The cockpit is actually torn off from the rest of the fuselage, which apparently also happened this time when the cockpit fell much earlier and lies farther away from the rest of the fragments.”

Morello reported from Kharkiv, Ukraine. Karoun Demirjian in Moscow contributed to this report.