Defense Department officials are claiming that the cost of the United States’ longest war in history will be $45 billion in 2018, which is actually double to estimate of what it would cost to end homelessness in the U.S. annually.

Randall Schriver, the assistant secretary of Defense for Asian and Pacific security affairs, said that he expects the Afghanistan war to cost American taxpayers $45 billion this year, which in addition to logistical support, will include about $13 billion for U.S. forces, $5 billion for Afghan forces, and $780 million for economic aid.

Schriver made the announcement during the Senate Foreign Relations Committee hearing on Tuesday. Deputy Secretary of State John Sullivan also spoke, and said he believes the United States’ policy “acknowledges that there isn’t a military solution or a complete solution.”

“I understand it’s America’s longest war, but our security interests in Afghanistan, in the region are significant enough … to back the Afghan government in their struggle against the Taliban,” Sullivan said.

Over 31,000 civilian deaths have been documented in Afghanistan following the U.S. invasion. The United Nations Assistance Mission in Afghanistan began documenting civilian casualties in 2009, and the combined number of civilians who were killed and injured that year was nearly 6,000. The number has steadily increased over the years, and in 2016, it reached a record high with nearly 3,500 killed and nearly 8,000 injured.

A report from the UNAMA noted that in 2017, the death rate for children increased by 9 percent over the previous year, and the death rate for women increased by 23 percent. The report also claimed that an increase in airstrikes has led to a 43 percent increase in causalities.

The Hill reported that the Defense Department officials did receive some criticism from senators such as Jeff Merkley, a Democrat from Oregon, who questioned why the Taliban would want a political settlement now when they already “control more territory than they did since 2001” when the U.S. invaded the country—claiming the purpose was to defeat the Taliban.

Sen. Rand Paul, a Republican from Kentucky, also criticized the massive 2018 budget for the Afghanistan War, and argued that after 16 years, Afghans still “don’t seem to be able to defend themselves,” and for U.S. taxpayers, billions of dollars are “just being thrown down a hatch in Afghanistan.”

“I think there’s an argument to be made that our national security is actually made more perilous the more we spend and the longer we stay there. … We’re in an impossible situation,” Paul said. “I just don’t think there is a military solution.”

Paul has a history of criticizing the amount of money the U.S. government spends in foreign countries, especially on wars in the Middle East. After Trump vowed to continue the longest war in U.S. history in August 2017, Paul criticized the move and asked when the U.S. would start focusing on its own country.