It was unknown if the two people shot were part of the wedding party or were there as guests.
He said Saturday's shooter arrived at the church after the wedding began.
The criminal investigation has been turned over to the New Hampshire Attorney General's Office and New Hampshire State Police Major Crime investigators.More news: Arkansas judge: Court to hear 19 adoption scheme cases
Police were called to the church shortly after 10 a.m.in Pelham, a town of about 13,000 on the border of MA.
The number of people injured is unknown.
Pelham is located about 40 miles (64 kilometers) south of Concord, New Hampshire's capital.More news: Gowdy joins Trump's personal legal team
WMUR's Amy Coveno reports that a celebration of life ceremony for Garcia was due to be held at noon on the day of the shooting.
The 60-year-old was killed earlier this month. Brandon Castiglione, 24, has been charged with second-degree murder in his death.
New Hampshire Governor Chris Sununu said that state officials are on scene assisting local first responders with the incident. Many people took to Twitter to point out that the New England Pentecostal Ministries is a network of Black churches and wondered whether it was racially motivated.
There have been no reported fatalities and few details on injuries.More news: Tottenham ace Christian Eriksen wants to leave in 2020
Multiple ambulances were called to the scene.