WARSAW—Poland's three-month-old government ordered a new investigation into the 2010 airplane crash in Russia that killed the country's president and 95 others, reviving a dispute that has strained relations with Russia and widened divisions at home.

The cabinet of the Law and Justice party, which won parliamentary elections in October, commissioned a report, to be prepared by 21 people appointed by the government.

Defense Minister Antoni Macierewicz said on Thursday that the Russian-made Tu-154 government jet carrying President Lech Kaczynski may have disintegrated midair on its approach to the Smolensk airport in western Russia. Mr. Macierewicz and others in the Law and Justice party have maintained that explosions were the only possibility that fully explained the crash.

According to official findings by a government-appointed committee in 2011, the plane descended too low in thick fog and crashed after hitting trees.

President Kaczynski and his delegation were on their way to a World War II commemoration of a Stalin-era massacre by the Soviet Union's secret police of more than 20,000 Polish prisoners of war in the woods near Katyn.

The previous centrist government of the Civic Platform party has called Mr. Macierewicz's allegations conspiracy theories. It supported the official Polish report, which largely agreed with findings of an earlier Moscow-based committee that Polish pilot error was mainly to blame, other than to partly blame Russian air traffic controllers.

The Law and Justice party's leader, Jaroslaw Kaczynski, lost his twin brother, President Kaczynski, in the crash. The president's wife, as well as scores of other officials—the central bank chief, top army commanders and legislators—were among the victims.

Mr. Kaczynski has referred to the victims as "fallen" and—to quote a Polish poet—"betrayed at dawn."

The Law and Justice party has maintained that political divisions were partly to blame. It said the previous government had tried to interfere with President Kaczynski's visit to Katyn. Some in the party have talked of an assassination plot without offering any evidence.

President Kaczynski was beginning his re-election campaign at the time of the crash. His brother then ran in his stead, but lost.

Despite initial appearances that Poland and Russia could overcome their differences, tensions between the historic foes increased in the aftermath of the crash. Russia has repeatedly refused to hand over the plane's wreckage to Poland until it has concluded its own criminal probe. A Russian foreign ministry spokeswoman said on Thursday the case had been fully clarified.

Meanwhile, Russia's annexation of Crimea further strained the relationship, with Poland leading Western criticism of Russia's support of separatist forces in eastern Ukraine.

Mr. Macierewicz on Thursday criticized the government of former Prime Minister Donald Tusk, now serving as president of the European Council, over its handling of the aftermath of the crash, including allowing a Moscow-based aviation committee to conduct the original investigation.

Mr. Tusk has insisted his government did its utmost to help the victims' families and ensure the continuity of key Polish institutions.

A court in Poland recently decided to continue a case brought by several relatives of some of the victims against Mr. Tusk's aides.

Write to Martin M. Sobczyk at martin.sobczyk@wsj.com

(END) Dow Jones Newswires

February 05, 2016 02:45 ET (07:45 GMT)