Botswana blamed Congolese President Joseph Kabila on Monday for his country's humanitarian and security crisis, in the sharpest criticism yet from an African government of his refusal to step down.
Western powers have repeatedly criticized Kabila whose mandate expired in December 2016, but African countries have trodden more gently, urging progress toward long-delayed elections but avoiding direct condemnations of Kabila.
Congo emerged in 2003 from a five-year war that killed millions, most from hunger and disease, and the current political crisis has contributed to a surge of conflict that has forced millions to flee their homes.
At least 22 people, including 15 civilians, were killed in the past two days in inter-ethnic clashes in eastern Congo's North Kivu province, a local official said.
"We continue to witness a worsening humanitarian situation in that country mainly because its leader has persistently delayed the holding of elections, and has lost control over the security of his country," Botswana's Ministry of International Affairs said in a statement.
Congo's foreign minister, Leonard She Okitundu, declined to comment.
Botswana's statement comes after the resignation of Kabila's close ally Jacob Zuma as South African president added to uncertainty about his standing among key African states.
Kabila is facing mounting pressure in the streets to organize prompt elections. Security forces killed at least two people at a church-led march on Sunday. More than a dozen protesters have been killed since December.
Police said on Monday that an officer had been arrested for violating orders by firing a rubber bullet at a protester from too close a range - less than 20 meters (yards), killing him.
However, a doctor at the hospital where the man, pro-democracy activist Rossy Mukendi, died on Sunday, told Reuters he had been hit in the heart by a bullet that had entered and exited his body.
The statement by Botswana, one of Africa's most stable democracies, urged "the international community to put more pressure on the leadership in the Democratic Republic of Congo to relinquish power and pave way for the ushering in of a new political dispensation."
Kabila denies he is trying to cling to power but has refused to publicly rule out trying to change the constitution to remove term limits that prevent him from running for re-election, as the presidents of neighboring Congo Republic and Rwanda have done.
Congo's political turmoil has emboldened the dozens of militia groups that operate in its mineral-rich eastern borderlands.
Fifteen civilians and seven militiamen were killed in two separate attacks on Sunday and Monday by the Hutu-dominated Nyatura militia, local administrator Hope Sabini told Reuters.
The Nyatura fighters were going after a Nande-dominated militia called Mai Mai Mazembe in the villages of Kalusi and Bwalanda, Sabini said.