Kenya will send 600 more police officers to Haiti next month to bolster an international anti-gang mission, President William Ruto said on Friday during a visit by the Haitian prime minister intended to speed up deployments to the force.

At least 10 countries have promised to send a total of about 2,900 troops to participate in the Kenyan-led Multinational Security Support (MSS).

But only about 430 have deployed since the U.N.-authorised mission got underway in June, nearly 400 of them from Kenya.

Heavily armed gangs, which control most of the capital Port-au-Prince, have continued to gain territory. Last week, members of the Gran Grif gang carried out one of the country's deadliest attacks in recent years, killing at least 115 people in a farming region, according to a local mayor.

Ruto told reporters the mission was improving security in Haiti, calling the fight against gangs "the battle that we can win". He said the additional 600 officers committed by Kenya were in training and would be ready for duty next month.

Standing next to Ruto, Haitian Prime Minister Garry Conille praised the police response to last week's massacre.

"The police and the (Kenyan) contingent were able to deploy by road within - really, virtually - hours to make sure that the city in question was quickly protected," Conille said.

Over 700,000 people in Haiti have fled their homes and over five million are going hungry - nearly half the population, according to the United Nations.

Last month, the U.N. Security Council unanimously authorised extending the MSS's mandate by another year. A U.S. push for a plan to turn it into a U.N. peacekeeping mission was dropped from the resolution due to opposition from Russia and China.