Kenya has threatened to take unspecified action against Eritrea on suspicion that the country is supplying the Somali militant group al-Shabab.

Kenya's foreign minister Moses Wetangula summoned Eritrea's ambassador for a meeting in Nairobi Friday. Afterward, he told a news conference that he had “raised concern” about intelligence Kenya has showing arms flowing from Eritrea to al-Shabab.

He said if that is indeed the case, Kenya has “a series of options” it could take, which he declined to identify.

United Nations investigators has also accused Eritrea of arming al-Shabab. Eritea has repeatedly denied the allegations, most recently this week, and calls the accusations “outright lies.”

Kenya sent troops into Somalia last month in pursuit of al-Shabab, which it blames for a series of cross-border kidnappings of foreigners.

The sides appear to have clashed only briefly so far, but Kenya has warned it may attack up to 10 towns in southern Somalia. Much of the area is controlled by al-Shabab, which is trying to overthrow the Somali government.

Kenya's military said Friday that it sunk a boat near the Somali town of Ras Kamboni, after the boat refused to stop for identification, and approached Kenyan Navy forces at a high speed.