(CNN) Foreign ministers whose countries form an anti-jihadist force in the Sahel region of Africa called on Washington to further support their effort Wednesday, as US counterterrorism operations in Africa are under the spotlight following the deadly ambush in Niger which killed four US soldiers.

"We are asking for an investment in our future," Abdoulaye Diop, Mali's foreign minister, told a Washington audience at the Center for Strategic and International Studies. Mali is the chair of the G5 Sahel force, made up of troops from Mali, Burkina Faso, Niger, Chad and Mauritania.

"We are not sitting and begging for the money. We are playing our part, but we shouldn't be left alone," he added. "We want the US to be a part."

The ministers were in Washington meeting with Trump administration officials after attending a UN Security Council meeting in New York on Monday to drum up international support for the force, which is set to begin operations this week. The five-nation force plans to build up to 5,000 military and police personnel by March 2018.

Western fears about the rise of extremist groups in Africa's desert Sahel region have grown since the fall of Libya in 2011.

Diop said the Sahel was facing a global threat, and warned if the vast arid region was not fully governed by governments, the consequences could reach Europe and the United States.

France, which supports a UN-mandate, has deployed thousands of troops to the region to combat jihadists.

The US had already been targeting ISIS in Libya and al-Shabaab in Somalia. But the growing US military presence in the region has drawn public attention after last month's ISIS ambush in Niger that killed four US servicemen while they were on a joint patrol with troops from Niger near the Niger-Mali border.

The Trump administration said Tuesday it would provide up to $60 million to the five-nation counterterrorism force. Secretary of State Rex Tillerson said in a statement that the funding will "bolster our regional partners in their fight to ensure security and stability in the face of ISIS and affiliated groups and other terrorist networks."

"This is a fight we must win, and these funds will play a key role in achieving that mission," Tillerson said.

But while it supports bilateral funding for the force in order to stabilize the region, Washington has balked at calls by France and the G5 nations themselves to put the force under a formal UN umbrella without a strategy for the operation.

"They can't show us a goal, they can't show us how they're going to proceed, " US Ambassador to the United Nations Nikki Haley told CNN in an interview Friday in Democratic Republic of Congo. Haley was on the last leg of her first tour as US envoy to the UN, which also took her to Ethiopia and South Sudan. "If they go back and they show us a strategy, and if it's something that General (James) Mattis and General (Joseph) Dunford feel like is moving in the right direction, then yes. We will. But right now they're not showing that, and so it doesn't make sense for us."

The African ministers blamed the 2011 NATO intervention in Libya in large part for the chaos plaguing the region, especially the movement of arms and people from Libya to the rest of the Sahel. Foreign minister Diop called the military action a "strategic mistake" and a "complete game-changer in the region" which was "ill-planned, ill-executed and the aftermath was not handled."

Boko Haram also took over swathes of Northeastern Nigeria and al Qaeda-linked groups took over northern Mali. While the situation in Mali has improved somewhat, attacks have spread to neighboring countries, which are poor and rife with political chaos.

"In Africa with all the challenges of the youth bulge, poverty, the lack of governance, wide open spaces, these are areas where violent extremist organizations, like ISIS or like al Qaeda, thrive," Thomas Waldhauser, the commander of US troops in Africa, told a small group of reporters in Africa last week.

Waldhauser also said the new force is exactly the type of partnership the US wanted to develop in the region.

"We want partner nations who share the same overall strategic objectives that we do," he added. "We want to try to foster that type of behavior."

But the US would prefer to fund the effort bilaterally, as opposed to via a UN mandate, Waldhauser explained, adding, "United Nations forces don't do counterterrorism, they do peacekeeping operations."

"One of the hardest things to do in an organization like that is to try to synchronize the efforts of those five countries and have a coherent strategy as opposed to just a series of engagements in different locations," he told the reporters traveling with Haley.

Foreign Minister Diop of Mali said that the group had shared a "conception of operation" with the US, but that they would provide more information on the regional strategy if necessary. He and the other ministers said curbing cross-border terrorism was the first-phase of a comprehensive approach that would ultimately include intelligence sharing and development for the region.

"This is not a panacea to the problems of the Sahel," Jennifer Cooke, director of the Africa program at CSIS, said of the G5 force. "But it is a first step toward addressing one of the central challenges, which is movement of arms and people and extremist groups across borders which has eluded these countries so far. The trans-border threat is an immediate problem that this joint force beings to fix. And it's a good first step toward getting these countries to cooperate."

The group has estimated that it would need a budget of nearly $500 million in its first year, but has only raised about one-quarter of that, with the European Union promising about $58 million, and each of the participating African governments committing a little over $11 million annually.

A donor conference will be held in Brussels on December 14.

During Wednesday's discussion at CSIS, the ministers said they needed additional technical, logistical and communications support, as well as intelligence sharing, to build the necessary capacity to fight extremists, which they argued the US has the best capability to provide.

"We know what we need to do this job," Diop said. "We just need maximum support."

"We are engaged in the fight but we need to be successful," Diop said. "If you don't have the resources, you are calling all the terrorists to rally to this place. And that could cause an even bigger problem."