MONTERREY, Mexico (AP) _ A crowd of 10,000 people marched in Monterrey to protest alleged vote fraud, which they claimed is depriving opposition candidate Fernando Canales Clariond of the governorship of northern Nuevo Leon state.

Both Canales and the ruling Institutional Revolutionary Party's candidate, Jorge Trevino, have claimed victory in last Sunday's election, even though the government has said it will not announce results before next Sunday.

Trevino, basing his claim on unofficial returns, said he won by 71 percent to Canales' 22 percent.

Chanting ''Canales yes, Trevino no,'' the crowd from Canales' National Action Party marched along a one-mile stretch of downtown Monterrey, then rallied outside the state mansion.

Many carried signs with the party's campaign slogan, ''Yes, it can be done.''

A group of demonstrators moved toward the doors to the mansion and waved huge banners that read ''Accept your defeat.'' A small group of policeman guarded the area, but did not interfere. There was no violence.

The crowd then carried a makeshift black coffin that read ''R.I.P. Jorge Trevino'' to the state legislative building, where the demonstrators peacefully dispersed.

National Action supporters nationwide accuse the Institutional Revolutionary Party - which has been in power for 56 years - of widespread fraud in last Sunday's midterm elections, which included races for governor in seven states.

Their leaders claimed that precinct chiefs from the Revolutionary Party, also known as PRI, barred National Action pollwatchers from voting stations, padded voter registration rolls, and stuffed ballot boxes with PRI votes even before the balloting began.

In a statement issued in Mexico City, the PRI claimed it achieved ''100 percent victory'' in the gubernatorial races as well as in elections for 300 of the 400 seats in the lower house of congress and a smattering of state legislatures and municipalities. The other 100 federal house seats are distributed among the minority party through a system of proportional representation.

Addressing the rally briefly, Canales claimed that his unofficial results showed he won 54 percent of the vote to Trevino's 44 percent and announced he petitioned the state legislature, demanding to be declared the victor.

Races for governor have been especially heated in Nuevo Leon and Sonora, on the west coast, where National Action has made strong inroads among voters in recent years.

In Sonora's capital of Hermosillo, National Action candidate Adalberto Rosas Lopez announced that his followers would take to the streets if his party's victories are not recognized by the government.

He told reporters his followers would wait to protest until official results are announced. ''I know we won, but I am sure they will refuse to accept our victory.''

In Mexico City, President Miguel de la Madrid urged a meeting of PRI peasant leaders to continue working for their party's revolutionary ideals, and said the party will not let ''confused minorities'' take power away from it.

PRI has held the presidency, all governorships and has dominated Congress since the party was founded in 1929. In the lower house of Congress, it holds 299 of the 300 seats filled by direct elections. PAN holds the other seat, along with half of 100 minority party seats.