MADRID -- Officials say they are struggling to free two ships that ran ashore on a stretch of ecologically valuable coastline in eastern Spain.

The cargo ships Sunrise and Celia were run aground by powerful wind on Sept. 28 south of the port city of Valencia.

The ships are carrying 180 metric tons of fuel, and officials are worried about oil and cargo spills. One of the ships is carrying empty containers and the other massive steel pipes.

The country's maritime authority said large dredgers arrived Sunday to begin trying to clear a channel to sea after previous attempts failed.

Just yards inland is Albufera Natural Park, wetlands used by many of Europe's migrating birds. Around the rim of the park, farmers have for centuries cultivated rice prized for use in paella.

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  • People look at a cargo ship which ran aground after a heavy storm at Saler beach near Valencia Saturday, Sept. 29, 2012. (Photo/Alberto Saiz)

  • People look at a cargo ship ran aground after a heavy storm at Saler beach near Valencia Saturday, Sept. 29, 2012. (AP Photo/Alberto Saiz)

  • Two girls running in front of a cargo ship which ran aground after a heavy storm at Saler beach near Valencia, Saturday, Sep. 29, 2012. (AP Photo/Alberto Saiz)

  • People look at a cargo ship ran aground after a heavy storm at Saler beach near Valencia Saturday, Sept. 29, 2012. (AP Photo/Alberto Saiz)

  • People look at a cargo ship ran aground after a heavy storm at Saler beach near Valencia Saturday, Sep. 29, 2012. (AP Photo/Alberto Saiz)

  • People look at a cargo ship which ran aground after a heavy storm at Saler beach near Valencia Saturday, Sept. 29, 2012. (Photo/Alberto Saiz)