Chechen-born Amina Okuyeva, a former pro-Ukraine, volunteer soldier in the Donbas military conflict against pro-Russian rebels, has been short dead in an ambush near the town of Hlevakha in the Kyiv region on October 30.

"Her car has been fired at from the bushes at the railway crossing near the town of Hlevakha," Anton Gerashchenko, an advisor to the country's Interior Minister Arsen Avakov, wrote on his official Facebook the same day.

According to local law enforcement agencies, Okyeva's husband, Adam Osmayev, a British-educated Chechen opposition activist suspected by Moscow of planning an attack on President Vladimir Putin, was wounded when their car came under fire at a railway crossing. His wife was shot in the head.

In June, Osmayev survived an assassination attempt on him in Kyiv that Ukrainian officials suspect was ordered in Russia, in which Akuyeva escaped without injury after using her own handgun to fire at the assassin as he shot her husband.

The Russian state is suspected of being involved in the assassination. A critic of both Putin and the head of the Chechen Republic Ramzan Akhmadovich Kadyrov, Osmayev was arrested in the Ukrainian city of Odesa in 2012. Officials in Russia and Ukraine at the time said the arrest was part of a joint operation to thwart an assassination plot against Putin. Osmayev was released after the change of government in Ukraine in 2014.

Ukraine has been hit by a wave of serious street incidents in recent months. Five days ago, Ihor Mosiychuk, a lawmaker from the Radical Party headed by Oleh Liashko, was injured in a bomb blast in Kyiv.

In June, a Ukrainian SBU security service colonel was killed in a car bomb explosion near the town of Kostiantynivka in the eastern Donetsk region. The incident followed the June 27 car bomb assassination of Maksym Shapoval, a colonel serving at the Ukrainian Defence Ministry's chief intelligence directorate.

On June 8, grounds around the US embassy in Kyiv were also hit by an explosion. It was caused by a small explosive device but there were no injuries or serious damage. On May 30, the former acting director of the state-owned spirits conglomerate Ukrspyrt Viktor Pankov was shot dead in Kyiv.