Myanmar government forces launched air strikes against ethnic minority guerrillas in two areas of the country on Wednesday, local reports said.

Fighting has been raging daily in northern Myanmar in territory controlled by the Kachin Independence Organisation, representing the Kachin minority, and in the east by the Karen National Union, representing the Karen.

Both groups have struck alliances with the popular movement opposing the military junta that seized power in the country in February after ousting the elected government of Aung San Suu Kyi.

Generally non-violent marches against military rule also continue in many cities and towns.

The Kachin and the Karen have been struggling for decades for greater autonomy from the central government and have their own well-armed and trained military units, whose help the protest movement has been seeking to counter the government’s armed might.

Colonel Naw Bu, a Kachin spokesman, said fighting against the junta’s forces intensified on Wednesday, reported 74 Media, an online news service in Kachin state.

It quoted him as saying that since Tuesday, the government has used heavy artillery and fighter jets to attack a Kachin position at the foot of Alaw Bum mountain. The position had been a government outpost but was seized by the Kachin on March 25.

He said heavy fighting has been continuing in the area for five days, causing most civilians to flee.

According to the UN Office for the Coordination of Humanitarian Affairs, clashes between the two sides have escalated since mid-March, with almost 50 armed confrontations. It said both sides have used mortar shelling.

Details of the fighting in both the Kachin and Karen areas were not possible to independently verify.

In eastern Myanmar, government aircraft continued to carry out air strikes in Karen state on Wednesday, according to aid groups active in the area – a day after Karen guerrillas overran an army base on the banks of the Salween river dividing Myanmar and Thailand.

Both the Karen Peace Support Network and the Free Burma Rangers confirmed a total of six air attacks involving jets and helicopters.

They said there were no known casualties but the Peace Support Network said about 300 villagers fled across the border.

There were also air attacks on Tuesday just hours after the Karen seized the riverside base.

The latest wave of air strikes increased fears that more villagers will abandon their homes in vulnerable areas, with many likely to try to cross into Thailand.

Fighting between the Karen and the Myanmar military has been intense since February.

Myanmar jets have bombed and strafed Karen villages since March 27, and its army has deployed new battalions to the area in possible preparation for a large-scale offensive.

Meanwhile, the European Union has extended for a year sanctions against senior officials in Myanmar, including junta leader Senior General Min Aung Hlaing, and others involved in the military coup in February.

The EU said the sanctions, which include asset freezes, travel bans, an arms embargo and restrictions on the export of equipment that can be used for military and police repression, will remain in place until at least April 30 2022.

“The sanctions target high-ranking officials from the Myanmar armed forces (Tatmadaw) and the border guard police, as well as civilian members of the State Administrative Council and the chairman of the Election Commission,” the statement said.

“The EU continues to stand with the Burmese people and will continue to provide humanitarian assistance,” it added.