Two Marine AH-1W Cobra helicopters, left, fly in a live-fire drill with two Jordanian AH-1F Cobras, May 24, 2012.

Despite Bahrain's bloody crackdown on pro-democracy protesters, the U.S. has continued to provide weapons and maintenance to the small Mideast nation.

Defense Department documents released to ProPublica give the fullest picture yet of the arms sales: The list includes ammunition, combat vehicle parts, communications equipment, Blackhawk helicopters, and an unidentified missile system. (Read the documents.)

The documents, which were provided in response to a Freedom of Information Act request and cover a yearlong period ending in February 2012, still leave many questions unanswered. It's not clear whether in each case the arms listed have been delivered. And some entries that only cite the names of weapons may in fact refer to maintenance or spare parts.

Defense Department spokesman Paul Ebner declined to offer any more detail. "We won't get into specifics in any of these because of the security of Bahrain," said Ebner.

While the U.S. has maintained it is selling Bahrain arms only for external defense, human rights advocates say the documents raise questions about items that could be used against civilian protesters.

"The U.S. government should not be providing additional military equipment that could make matters worse," said Sunjeev Bery, Middle East advocacy director for Amnesty International USA.

There have been reports that Bahrain used American-made helicopters to fire on protesters in the most intense period of the crackdown. Time magazine reported in mid-March 2011 that Cobra helicopters had conducted "live ammunition air strikes" on protesters.

The new Defense Department list of arms sales has two entries related to "AH-1F Cobra Helicopters" in March and April 2011. Neither the exact equipment or services being sold nor the delivery timetable are specified.

The U.S. is also playing a training role: In April 2012, for example, the Army News Service reported that an American team specializing in training foreign militaries to use equipment purchased from the U.S. was in Bahrain to help with Blackhawk helicopters.

Bahrain's ambassador to the U.S., Houda Nonoo, said the country's military has not targeted protestors. Bahrain's military "exists to combat external threats," Nonoo told ProPublica. "[T]he potential for U.S. foreign arms sales to be used against protestors in the future is remote."

The Obama administration has stood by Bahrain's ruling family, who are Sunni, during nearly two years of protests by the country's majority Shia population. Bahrain is a longtime ally and the home to a large American naval base, which is considered particularly important amid the current tensions with nearby Iran.

The itemized arms sales list does not include dollar values but a separate document says military equipment worth $51 million was delivered to Bahrain in the year starting in October 2010. (That period includes several months before the protests began.)

The U.S. has long sold weapons to Bahrain, totaling $1.4 billion since 2000, according to the State Department. The sales didn't come under scrutiny until security forces killed at least 19 people in the early months of the crackdown in 2011. (Dozens have died since then.)

The administration put a hold on one proposed sale of Humvees and missiles in Fall 2011 following congressional criticism. But Foreign Policy reported that other unspecified equipment was still being sold without any public notification.

The new documents offer more details on what was sold during that period — including entries related to a "Blackhawk helicopter armament" in November 2011 and a missile system in January 2012.

In May 2012, the administration announced it was releasing some unspecified items to Bahrain's military that "are not used for crowd control" while maintaining a hold on the Humvees and TOW missiles.

State Department spokesman Noel Clay told ProPublica, "We continue to withhold the export of lethal and crowd-control items intended predominately for internal security purposes, and have resumed on a case-by-case basis items related exclusively to external defense, counter-terrorism, and the protection of U.S. forces."

The U.S. has also sold Bahrain a helicopter fit for the royal family.

In September, Missouri-based aviation services firm Sabreliner reported that, as part of an official government arms sale, it delivered to Bahrain a fully customized UH-60 Blackhawk Helicopter for "a variety of missions including transporting heads of state." The aircraft was outfitted with a "clam shell door" for ease of entry, a "new VIP interior," and a "custom Royal Bahraini" paintjob.

In other recent developments in Bahrain, the country's highest court this month upheld lengthy prison sentences for 13 high-profile activists accused of plotting to overthrow the government.

In a rare occurrence in November, a series of homemade bombs were set off in the capital of Manama, killing two and leading some observers to argue that the opposition is growing more militant. Also in November, an Amnesty International report found that despite government promises, "the reform process has been shelved and repression unleashed."