MANILA (Reuters) - The United States provided the Philippines with $127 million in security assistance in the 12 months ended in September, the biggest sum in about 15 years, overlapping with a stream of angry threats from President Rodrigo Duterte to sever their defense alliance.

Philippine President Rodrigo Duterte points to photographers during an awarding ceremony for outstanding government workers, at the Malacanang Palace in Manila, Philippines December 19, 2016. REUTERS/Ezra Acayan

The U.S. embassy in Manila on Friday confirmed its longtime Asian ally had received a 154 percent increase in military assistance from the 2014-2015 period, the biggest sum since American forces returned to the Philippines in 2002.

The United States fiscal year runs from Oct. 1 to Sept. 30. The aid boost went mostly into items such as communications equipment, small arms, replacement parts for hardware and coastal radar for maritime security.

The U.S. embassy said the military assistance for the current fiscal year had yet to be finalised. Duterte has spoken positively about President-elect Donald Trump, although his election win in November has not stemmed the flow of his anti-U.S. rhetoric.

The increased spending was agreed when President Barack Obama visited Manila last year, amid high tension between the Philippines and China in the South China Sea, and was part of a renewed commitment made to Manila in a 2014 Enhanced Defence Cooperation Agreement (EDCA).

Duterte has a strong dislike for Obama and during regular tirades has voiced disdain for EDCA, which allows U.S. forces rotational access to some military bases. He has accused the former colonial power of hypocrisy and bullying, threatened to rescind EDCA, and doubted that the U.S. would honor its treaty commitment to defend the Philippines if attacked.

His foreign policy approach has been to court Russia, and ironically, historic foe China. He said he wants to procure weapons from both countries so that Philippine forces do not have to depend on “hand-me-down” American hardware.

Confirmation of the boost in military aid from about $50 million annually over the past two fiscal years to $127.1 million in 2015-2016 comes amid concerns in Washington not only about Duterte’s anti-U.S. stance, but his bloody war on drugs.

His vitriol against the United States started in August and intensified the following month after Obama insisted he would raise his concerns about the drugs crackdown directly with Duterte. The meeting was scrapped after Duterte called Obama a “son of a bitch”.

More than 6,000 people have been killed in the crackdown during his six months as president, a third by police and the rest still being investigated and widely assumed to be drugs-related murders.

Some U.S. legislators are concerned U.S. aid could in some way be used to support Duterte’s war on drugs.

Three members of the Senate Committee on Foreign Relations on Thursday issued a letter to the State Department asking for full disclosure by Jan. 13 on financial giveaways and assistance to the Philippines.

“We urge the U.S. to denounce these horrific violations of basic human rights, and ensure that no foreign assistance is being provided to support egregious acts against humanity,” said Democrat Senators Edward Markey and Chris Coons, and Republican Marco Rubio.

In an email to Reuters, the U.S. embassy broke the 2015-2016 aid down to $50 million in foreign military financing, $1.9 million in international military education and training, $42 million for a maritime security initiative and $33.2 million for counter terrorism activities.