U.S. presidential candidates John McCain and Barack Obama raised about the same amount of money in May.

Figures released by their campaigns show Democrat Obama brought in $21.9 million. Republican McCain reported $21.5 million raised in May. Since their respective presidential campaigns began, Obama has raised more than twice as much money as McCain.

On the campaign trail Friday, McCain traveled to Canada, where he delivered a speech supporting the North American Free Trade Agreement (NAFTA), a pact that Obama has criticized.

McCain told a group of business leaders in Ottawa that if he is elected, the United States will honor its international commitments to NAFTA.

During the Democratic primary, Obama said the U.S. should negotiate with Canada and Mexico to add tougher environmental and labor rules.

On Friday, Obama launched an attack against McCain's proposal to allow offshore oil drilling in U.S. coastal waters. Obama said the proposed drilling would not lower fuel prices for many years.

McCain opposed such drilling when he ran for president in 2000, but this week he said he supports giving individual states the right to decide whether to allow oil drilling.

Separately, the Obama campaign announced that the Illinois senator will campaign next week for the first time with former rival Hillary Clinton. Obama's campaign said the two senators will campaign together June 27, but it released no further details.

These meetings are a step towards unifying the Democratic Party after a long and bruising primary campaign in which Obama clinched enough delegates to secure the party nomination.

Some information for this report was provided by AFP, AP and Reuters.