WASHINGTON (Reuters) - Federal health officials, scrambling to fund efforts to combat the spread of the Zika virus in the United States, said on Tuesday they have provided more stopgap money to various locales while calls grew for Congress to cut short its recess and act.

Concern is mounting about the threat posed by the mosquito-borne virus after authorities in Florida last week reported the first signs of local transmission of Zika in the continental United States.

The Florida Department of Health on Tuesday said it was investigating one more case of locally transmitted infection, bringing to 15 the number of people infected by the bite of local mosquito in the same one square mile (2.6 square km) area of Miami-Dade County.

President Barack Obama in February asked the Republican-led Congress to approve about $1.9 billion in emergency funds to fight Zika at home and abroad and pursue a vaccine, but lawmakers have not passed funding legislation.

The Centers for Disease Control and Prevention said it provided more than $16 million to 35 states and five territories to help detect any cases of microcephaly, a birth defect marked by small head size that can lead to severe developmental problems in babies, and other Zika-related conditions.

U.S. health officials have concluded that Zika infections in pregnant women can cause microcephaly.

"These awards are a stopgap diverted from other public health resources until Zika funds are provided by Congress," the CDC said in a statement.

CDC provided $25 million last month in similar stopgap funding.

Republican Florida Senator Marco Rubio, seeking re-election this year after an unsuccessful bid for his party's presidential nomination, called on the Senate to interrupt its summer recess to pass Zika legislation.

"I hope we'll return to Washington quickly, take a day and just pass this funding measure so we can start to get funds flowing," Rubio said on Monday in Clearwater, Florida.

A $1.1 billion compromise bill failed after House of Representatives Republicans attached language that would impose restrictions on abortion and defund part of Obama's signature 2010 healthcare law.

Rubio said that while he prefers Obama's $1.9 billion figure, he believes there are enough votes in Congress to win passage of the $1.1 billion compromise.

Democratic Florida Senator Bill Nelson and Senate Democratic Leader Harry Reid also have called on Congress to reconvene to address Zika funding.

In an opinion piece in a newspaper in his home state of Kentucky, Senate Majority Leader Mitch McConnell blamed Democrats for the failure to pass Zika funding. McConnell urged the Obama administration in the interim to "aggressively use funds already available to strengthen our defense against the virus," saying hundreds of millions of dollars in funds that could be used were "seemingly unspent."

The CDC on Monday recommended that pregnant women avoid Miami's Wynwood neighborhood due to Zika infections there.

The Zika outbreak is affecting large parts of Latin America and the Caribbean, with Brazil the hardest hit so far.

(Reporting by Natalie Grover in Bengaluru and Toni Clarke in Washington; Additional reporting by Rick Cowan in Washington; Editing by Will Dunham)