Israeli forces have boarded two pro-Palestinian activist ships in international waters, as they were trying to break Israel's blockade of Gaza.

The Israeli defense forces spokesperson said in a statement that the boarding Friday was carried out in line with directives from the government after attempts to prevent the vessels from reaching Gaza were made.

There were no reports on injuries.

The Israeli navy is escorting the ships to the Ashdod port, where the activists will be transferred into the custody of the police and immigration authorities.

Earlier, the IDF had posted on YouTube a video showing what it said were Israeli naval officers warning the activists' ships that they were attempting to breach a legal blockade. The video also showed the naval officer offering the activists access to Israel for the transportation of their cargo to Gaza.

A spokeswoman for the activists told VOA earlier that the ships are carrying medical supplies and letters of solidarity for the Palestinian people. Contact with the ships was lost shortly after two Israeli navy vessels intercepted them Friday evening local time.

The 27 activists from countries including the United States, Canada, and Ireland set sail from Turkey on Wednesday. They say their goal is to deliver medical aid directly to Palestinians in Gaza, in defiance of Israel's blockade.

Israel imposed a naval blockade on the Hamas-ruled territory in 2007 in what Israeli officials say is a bid to keep weapons from reaching militants in Gaza.

On Thursday, the U.S. State Department renewed a call for Americans to avoid participating in the flotilla, saying they could face legal consequences. At least two Americans are on board.

Last year, nine activists were killed after Israeli commandos stormed a Turkish-led aid flotilla headed for Gaza. The confrontation caused a deterioration in relations between Turkey and Israel.

In July, pro-Palestinian activists launched an unsuccessful attempt to reach the Palestinian territory.