SKOPJE (Reuters) - A Macedonian court sentenced 33 ethnic Albanians to jail terms on Thursday, including seven given life sentences, after they were found guilty of plotting attacks and clashing with the police in a 2015 shootout in which 22 people were killed.

The 33 were accused of being part of a group of Albanian gunmen involved in the May 9, 2015 shootout with police in the northern Macedonian town of Kumanovo, in which eight police officers were among those killed and dozens were wounded.

Some of the defendants were from neighboring Kosovo, while others were from Macedonia’s own Albanian minority.

“The evidence offered by the prosecutor shows that the accused committed the criminal acts of terrorism and terrorist organization,” the presiding judge said.

The court was under heavy police protection, with helicopters flying overhead. The defendants protested while the verdict was being read, prompting the judge to order 33 of them to leave the courtroom before hearing sentences.

The 2015 shootout occurred during a police raid that followed an attack by armed men on a border post. Some of them were former guerrillas from the National Liberation Army (NLA), an ethnic Albanian militia that had fought an insurgency in 2001 in which scores of people were killed.

The NLA disbanded in 2002 and some of its former leaders entered the government.

Naser Raufi, one of the defense lawyers, said the trial was staged and that he did not expect to see such lengthy sentences.

“This calls for an independent investigation,” he said.

Macedonia, a small ex-Yugoslav republic of about two million people, declared independence in 1991 and mostly avoided the violence that accompanied the break up of Yugoslavia in the 1990s, until the clashes with ethnic Albanian fighters in 2001.

Albanians are believed to make up around 30 percent of Macedonia’s population, living mostly in the northwest near the borders with Kosovo and Albania.