Huddled on a vacant parking lot, about 150 Hispanic pastors and church members from across the city mingled and waited for the signal that their late Tuesday night prayer gathering was to start.

Security lights illuminated the asphalt. Blasts of traffic blared above from a highway overpass. A pastor directed them to clasp hands in a giant circle and shouted, “Vamos a orar.”

A vociferous free-for-all erupted. Some jumped up and down — their heads pointed upward and necks strained to maximize volume. Others bowed their heads, furrowed their brow and uttered inward requests to God.

They pleaded for Christian unity and spiritual revival in San Antonio and then took the crusade on the road — loading up vans and a bus — for a trip around Loop 1604.

It was a spiritual precursor, they said, to a rare prayer summit tonight at the Convention Center, one that has the potential to unite Spanish-speaking evangelicals closer than ever in recent history.

Called “Un Continente, Una Oracion” or “One Continent, One Prayer,” organizers expect more than 2,000 people — some from Dallas, Houston and the border cities.

If Tuesday night’s preparatory event is an indicator, it’ll have a heavy Latino-charismatic flavor: rock-style worship songs and motivational messages, including one from Oak Hills minister and former missionary to Brazil Max Lucado. The atmosphere will underscore the unusual break from isolation in this community, organizers said.

“Everyone has been working on their own and nothing’s happening,” said Fernando Ruiz De La Rosa, the main organizer and owner of “Radio Ola FM,” an evangelical Spanish-language station. “With the fellowship created by this event, we’re going to fight against disunity and lack of trust.”

The movement behind tonight’s event originated in Mexico earlier this year. From 15,000 to 20,000 people, mostly Protestants, filled plazas for ecumenical prayer in four Mexican states. The movement is partly a response to recent turmoil throughout the country, such as the outbreak of the swine flu, economic collapse and drug-related violence, Ruiz said.

It falls in line with the boom in charismatic-Pentecostal Christianity in Latin America, whose growth and organization is beginning to influence the U.S. Hispanic landscape.

San Antonio was the first U.S. city that leaders of the Mexican prayer movement chose for a meeting.

It’s a sort of “reverse missionary movement” marked by a broader ecumenical spirit than that shown by its English-speaking, Anglo counterparts whose historic role in initiating Latin American ministries is shrinking, said Luis Lugo, an expert in Latino religions and director of the Pew Forum on Religion and Public Life.

Diverse Latino Christians often share charismatic beliefs in divine healing, speaking in tongues and exuberant worship, which surface at prayer and worship gatherings as a unifying force.

“There’s a strong sense of angels and demons being active in the world,” Lugo said. “And so they see their role as claiming towns and countries for Christ.”

In San Antonio, about 100 pastors formed the nucleus to foot the $10,000 in costs and provide leadership for tonight’s event. The city’s two major Hispanic ministerial alliances and a host of smaller ones make up a steering committee. Beefing up the event is support from two North Side megachurches: Oak Hills Church and Cornerstone Church through their Hispanic ministries.

By making prayer the central platform and equalizing leadership across denominations, the movement has attracted Baptists, Methodists, Pentecostals and independents in Mexico, Ruiz said, a formula that is working here as well.

Ruiz is himself a pastor in Piedras Negras, Mexico, and a community relations representative for the state of Coahuila. He helped facilitate the prayer movement in Mexico, where some Catholics unofficially took part.

Father Bob Hogan, liaison for ecumenical and interfaith relations for the Archdiocese of San Antonio, said he hadn’t heard of any Catholics attending the event. He learned of it too late to consider going this year, he said.

Instead, Hogan, who hails from the Catholic charismatic community, said he will honor plans to take part in another ecumenical prayer event this weekend called Church of the City Sunday.

That event, in its fourth year, has unified Protestant and Catholics with evangelical and charismatic ties. Its chief organizer, Duke Jonietz, will pray briefly at the Hispanic event as a show of support.

Organizers of tonight’s event say their prayers will bring about concrete results in San Antonio: a drop in suicide, divorce and drug addiction and the strengthening of marriages and families. Those were the topics of prayer on a bus loaded with local pastors Tuesday night.

Many lifted their hands as they shouted out prayers spontaneously and repetitiously, stopping only for a sip of water or to hear instructions from Ruiz to look out their windows into the neighborhoods passing by. Recite prayers for friends who live there, businesses, churches and schools, he said.

Prayers quickly roared across the bus in a mix of Spanish and Holy Ghost-inspired “tongues.” Several ministers poured olive oil out a window to bless the land underneath.