A group of researchers in Japan says the use of words related to medical care shot up in tweets written in Ukrainian soon after the Russian invasion.

The group at Tohoku University's International Research Institute of Disaster Science analyzed more than 98.5 million tweets written in Ukrainian posted between November 1 last year and August 10.

The group released the results on Tuesday.

It says the number of instances of the words "drug" and "medical institution" spiked shortly after the start of the invasion in February, and that tweets including the phrase "medicine for diabetes" jumped 43-fold.

The researchers say more people apparently were worried about whether they could continue to receive treatment for chronic diseases.

They say the number of tweets containing "childbirth" and "newborn" also increased following the invasion. They say this indicates that pregnant women and medical workers sought places where expectant mothers could give birth safely.

The researchers say that as the invasion continued, the number of terms showing signs of psychological pain and anxiety, such as "despair," stood at 1.5 times the pre-invasion level.

They call for paying attention to whether the number of people complaining of symptoms of depression or post-traumatic stress disorder will increase further.

Fujii Susumu, associate professor at the institute, spoke at a news conference. He said more diverse and international support will be needed for Ukraine, and that he hopes for new concrete actions as the situation in the country has become clearer.