Colombian court suspends U.S. military base deal

* Declines to rule on legality of pact

* Court says it only analyzed way deal was approved

* Colombia is closest U.S. ally in region

BOGOTA, Aug 17 (Reuters) - Colombia's Constitutional Court suspended a deal on Tuesday giving U.S. troops more access to Colombian bases, sending the agreement back to President Juan Manuel Santos to seek congressional approval.

Bogota and Washington signed a pact last year increasing U.S. access to the Andean nation's military bases to boost anti-drug and counter-insurgency operations. It has been harshly criticized by leftist neighbors Ecuador and Venezuela.

"The Constitutional Court of Colombia ... resolves to refer to the president the supplementary agreement for cooperation and technical assistance in defense and security between the governments of Colombia and the United States," it said.

The court said the deal could not come into force until it had been approved by Congress. It added that it was not ruling on the legality of the agreement and had only analyzed the way the pact was approved.

The government of Santos, who took over the presidency on Aug. 7, has a comfortable majority in the legislature and will likely be able to pass the agreement.

The government said it would abide by the court's decision and would study the ruling.

Former Colombian President Alvaro Uribe decided last year not to send the bases deal to Congress for consideration. The accord has been criticized for granting U.S. troops immunity from criminal prosecution in Colombia.

Bogota and Washington signed the agreement in October giving U.S. troops access to seven bases. Officials say the U.S. military presence will not exceed caps previously set by the U.S. Congress of 800 military personnel and 600 contractors. [ID:nN30399219] (Reporting by Monica Garcia and Luis Jaime Acosta; Writing by Jack Kimball. Editing by Chris Wilson)